Accessories

Somewhere in my second year of building keyboards, I bought a 120-pack of switch films because a video told me every switch “needs” them. I filmed an entire board’s worth of premium switches that already felt fantastic, and I genuinely could not tell the difference in a blind test against my own unfilmed board. That taught me the single most important thing about switch films: they are a fix for a specific problem, not a universal upgrade.

This guide explains exactly what switch films do, how to tell if your switches actually need them, which material to buy, and how to install them properly, so you don’t waste money on films your switches don’t need.

⚡ Quick Answer

Switch films are thin pieces of plastic, usually polycarbonate (PC) or PET, installed between a switch’s top and bottom housing to fill manufacturing gaps. They reduce housing wobble and tighten the sound profile. You don’t need them on every switch. They help most on switches with looser tolerances (budget switches, older or worn switches) and provide minimal benefit on already-tight premium switches. Test for wobble first before buying films for an entire board.

1. What Are Switch Films, Exactly?

A switch film is a thin, precisely cut piece of plastic, most commonly polycarbonate (PC) or PET (occasionally PORON foam), shaped to fit the rim where a switch’s top housing meets its bottom housing. During manufacturing, these two halves are produced to a tolerance, and that tolerance leaves a microscopic gap. The film fills that gap.

🎯 What It Fixes

Housing wobble: the small lateral or rotational movement of the top housing relative to the bottom housing during a keystroke.

🔊 Side Effect

A tighter housing fit changes the acoustic resonance of the switch, typically producing a deeper, more controlled sound, what the community calls “thock.”

2. Why Housing Wobble Happens

Every switch housing is injection-molded, and even tight tolerances leave a small gap between the top and bottom pieces. This gap allows slight lateral and rotational movement during a keystroke, what enthusiasts call “wobble.” Older switches, worn switches, and budget switches tend to show more wobble because of looser tolerances or material wear over time.

Wobble is rarely large enough to see, usually well under half a millimeter, but it is very audible. It manifests as a hollow, inconsistent “clack” rather than a clean, controlled sound, and it can make a keyboard feel less premium even when the switches are otherwise good quality.

3. Do You Actually Need Films?

🧪 The Wobble Test (do this first). Hold a single switch and gently try to rock the top housing side to side relative to the bottom. If you feel noticeable movement or hear a faint rattle, your switches will likely benefit from films. If the housing feels solid with essentially no perceptible movement, films will provide minimal improvement, so save your money.

Switch Profile	Films Likely To Help?	Why
Budget switches (Outemu, basic Akko)	✅ Yes	Looser factory tolerances are common
Older or heavily-used switches	✅ Yes	Plastic wear increases the housing gap over time
Known “loose batch” switch models	✅ Yes	Community-documented tolerance issues
Premium switches (Gateron Ink, Oil Kings)	⚠️ Maybe	Tighter tolerances, test before buying
New switches with tight factory fit	❌ Unlikely	Already minimal gap to fill
Pre-filmed switches from manufacturer	❌ No	Already addressed at the factory

📌 Test before you commit. Film 5–10 switches first and compare them against unfilmed switches in a side-by-side type test. If you can’t tell the difference, you’ve saved yourself the time and cost of filming an entire keyboard’s worth of switches.

4. Film Materials: PC vs PET vs PORON

Polycarbonate (PC) films are the most rigid and produce the tightest housing fit, maximising the deep “thock.” PET films are slightly less rigid, offering a more moderate tightening effect. PORON foam films are soft and compressible, used less often, mainly on very loose or worn switches where a harder film might not seat well.

Material	Rigidity	Sound Impact	Best For
Polycarbonate (PC)	High	Maximises thock depth	Enthusiasts wanting max sound impact
PET	Medium	Subtle, balanced tightening	General improvement, budget option
PORON foam	Low (compressible)	Dampens, slightly muffles	Very loose or old switches, quiet builds

5. Choosing the Right Thickness

Most switch films are sold in 0.125mm and 0.15mm thicknesses, with some 0.2mm options for switches with larger housing gaps. The general guidance:

0.125mm: a safer, more conservative starting point, particularly for switches you suspect already have tighter tolerances.
0.15mm: the most common recommendation, providing noticeable wobble reduction for the majority of switches.
0.2mm: reserved for unusually loose housings; can occasionally cause reassembly difficulty if the gap is smaller than expected.

⚠️ Too thick can cause problems. If a film is thicker than the actual housing gap, the top housing sits slightly raised, making the switch harder to snap together or adding a slight increase in actuation force. If you feel resistance during reassembly, try a thinner film.

6. How to Install Switch Films

Open the switch with a switch opener, separating the top housing from the bottom. Set the stem and spring aside.
Position the film over the bottom housing rim. Most films have cutouts that align with the internal posts and the gold contact leaf, so do not cover the leaf.
Check alignment. The film should sit flush with no overhang or wrinkling. Use tweezers for fine adjustment.
Reassemble. Return the spring and stem, then snap the top housing back on. If it needs excessive force, the film may be too thick.
Test. Press the switch and listen. A properly filmed switch should sound and feel noticeably tighter than before.

💡 Film before you lube. Handle the dry housing and film first, then apply lubricant to the stem and rails after the film is seated. See our switch lubing guide for the full process to pair with filming.

7. Common Misconceptions

🚫 “All switches need films.” False. Many modern premium switches already have tight tolerances and show minimal improvement. Test before committing to a full board.

🚫 “Thicker films are always better.” False. A film thicker than the actual gap can cause reassembly issues or a slight increase in actuation force. Start with 0.15mm unless you have a specific reason to go thicker.

⚠️ “Films will fix a scratchy switch.” Films address housing wobble, not internal friction. Scratchiness is a lubrication issue. Films and lube solve different problems and work best together, not as substitutes.

8. Frequently Asked Questions

What are switch films?

Switch films are thin pieces of plastic, typically polycarbonate (PC) or PET, that fit between a switch’s top and bottom housing. They fill the microscopic manufacturing gap between the two halves, reducing wobble and tightening the switch’s sound.

Do all switches need films?

No. Switches with already-tight tolerances, including many modern premium switches, show minimal improvement from filming. Films help most on looser housings: budget switches, older or worn switches, and certain batches known for looser tolerances.

How do I know if my switches need films?

Hold a switch and gently rock the top housing side to side relative to the bottom. Noticeable movement or rattle means films will likely help. A solid feel with no perceptible movement means films will provide minimal improvement.

What is the difference between PC and PET switch films?

Polycarbonate (PC) is more rigid and provides the tightest housing fit, maximising the deep thock sound. PET is slightly less rigid, offering a more moderate tightening effect. PC is the popular choice for maximum sound impact; PET is a reasonable middle ground.

Do switch films affect tactile bump or click feel?

Properly installed films sit at the housing seam, not at the stem’s tactile legs or click mechanism, so they shouldn’t meaningfully affect bump or click feel. A film that is too thick can occasionally introduce slight stem binding, so stick to 0.15mm unless you have a specific reason to deviate.

How long does it take to film a keyboard’s worth of switches?

Filming a 60–80 key keyboard typically takes 1–2 hours depending on experience, similar to lubing. Many enthusiasts film and lube in the same session since both require the switch to be disassembled.

Can switch films damage my switches?

Films are generally safe when correctly sized and carefully installed. Risks are limited to using the wrong thickness or excessive force during reassembly. There is no permanent modification involved, you can remove the film at any time.

⚡ Quick answer

O-rings are small rubber rings that sit on the keycap stem. On a compatible MX-style keycap, the ring can contact the switch housing near the end of a press and cushion bottom-out impact. They are removable and inexpensive, though results depend on the keycap and switch geometry. What they don’t change: upstroke noise, spring ping, stabilizer rattle or a hollow-sounding case. WASD lists 0.2 mm and 0.4 mm travel reductions for its two ring models; actual change can vary with the keycap and switch.

O-rings are a low-cost way to address bottom-out clack on a compatible mechanical keyboard, but they are often misunderstood. This guide explains what they physically do, the sizes they actually come in, what changes and what doesn’t, and how they compare with stabilizer tuning and silent switches, so you can tell whether they’ll fix the noise that’s bothering you.

What O-rings actually do

At the end of travel, the switch stem or keycap can make a hard stop, producing a bottom-out clack. An O-ring on the underside of a compatible keycap can meet the switch housing before that hard stop and cushion the press. Exact contact depends on keycap shape and switch design.

Original Clickyboard diagram. The ring can cushion bottom-out when keycap and switch geometry allow it.

Because the ring stops the cap slightly early, the key travels a little less. The actuation point is usually before bottom-out, so a properly sized ring should not prevent registration. Short-travel switches and unusually thick rings need extra care: test one key to confirm full actuation and comfortable reset.

O-ring sizes: the published numbers

Listings use confusing labels, so here are the figures makers and sellers publish. These are published specs, not our own measurements.

Ring	Size (outer × inner × thickness)	Hardness	Travel reduction
Typical generic MX O-ring	8 × 5 × 1.5 mm	Usually 40A to 50A	Not usually stated
WASD red 40A-L	About 1.5 mm thick	40A (softer)	0.2 mm
WASD blue 40A-R	Slightly thicker than the 40A-L	40A (softer)	0.4 mm

Two things to know. WASD’s 0.2 mm and 0.4 mm figures describe intended travel reduction, not the ring’s physical thickness. The “A” number is Shore A hardness: a higher number means firmer rubber. Check the keycap-stem fit and test one key before buying a full set. See WASD’s installation and travel guidance.

What changes and what doesn’t

Part of the sound or feel	With O-rings
Bottom-out impact (the “clack”)	Softer and quieter
Bottom-out feel	Softer; firmer rings (50A+) change it less
Total key travel	Often shorter; WASD lists 0.2 or 0.4 mm for its models, but fit varies
When the key registers	Usually unchanged if the ring fits and the switch can still actuate fully
Upstroke (the key snapping back up)	No change: that noise is inside the switch
Spring ping, switch scratch	No change
Stabilizer rattle on the spacebar and long keys	No change
Hollow or echoing case	No change

How to judge it on your own board: we haven’t published recordings of our own yet, so the best evidence is your own before and after. Put rings on half the keys only. Record yourself typing the same sentence on each half with your phone at a fixed distance, and with any automatic noise reduction turned off. Listen for the bottom-out specifically; if the loudest sound is a rattle or ping, O-rings won’t touch it.

The trade-offs

Shorter, softer presses. Some people like the cushioned landing; others find it mushy, especially with soft 40A rings or on tactile switches, where it can blur the end of the press.
Only one kind of noise. They don’t address the upstroke, spring ping, stabilizer rattle or case echo, so on some boards the improvement is smaller than you hope.
Fiddly to fit. Every key needs a ring, and rings can fall out of keycaps when you pull them later.
Fit varies. Most fit MX-style stems, but very thick rings can stop some keycaps sitting properly. Try a few keys before doing the whole board.

How to choose

If you want…	Choose
The least change to feel	A thin, low-reduction ring (0.2 mm, such as a 40A-L type)
The most dampening	A 0.4 mm reduction ring in softer 40A
Less clack but a crisper bottom-out	A firmer ring whose size fits your keycap
To find out if you like them at all	A cheap bulk pack, tried on a few keys first

Whatever you buy, check the listing says it fits MX-style (Cherry MX) stems, and get enough for every key plus spares: about 61 for a 60% board, 87 for a TKL and 104 for full-size.

Check O-ring sets on Amazon

Budget bulk pack on Amazon

Affiliate links: if you buy through them we may earn a small commission at no extra cost to you.

O-rings vs stabilizer tuning vs silent switches

These fix different noises, so the right one depends on what you hear. None is simply “best”.

Fix	What it quietens	Cost and effort	Changes feel?	Reversible?
O-rings	Bottom-out clack only	Low-cost; installation time varies by board size	Yes: shorter, softer bottom-out	Yes
Stabilizer tuning	Rattle and ticking on the spacebar, Enter, Shift and Backspace	Lube and tools; about an hour	Smoother long keys	Mostly
Silent switches	Bottom-out and upstroke, inside the switch	A full set of switches; easy on hot-swap boards	Slightly softer, slightly shorter travel on some models	Yes, on hot-swap boards
Case foam	Hollow echo from the case	Cheap; means opening the case	Little or none	Yes

If your loudest sound is a rattly spacebar, start with the stabilizers. If it’s every key clacking at the bottom, O-rings or silent switches are the fix. If the keyboard sounds hollow, look at foam. Plenty of quiet boards use more than one.

How to install O-rings

Pull a keycap with a keycap puller, straight up. On hot-swap boards, go gently so you don’t pull the switch out with it.
Push one ring over the stem on the underside of the keycap until it sits flat at the base.
Press the keycap back on firmly until it’s fully seated.
Try a few keys first. Confirm each key still registers and returns normally, then fit the rest if you like the feel.
Type on it for a day. Too soft? Try a thinner or firmer ring. Not enough difference? Your noise is probably coming from somewhere else; see the table above.

Frequently asked questions

Do O-rings make a keyboard quieter?

Yes, but only the bottom-out: the clack when the keycap hits the switch at the bottom of the press. They do not change upstroke noise, spring ping, stabilizer rattle or case echo, so how much quieter a board gets depends on where its noise comes from.

What size O-rings fit a mechanical keyboard?

For standard MX-style keycaps, the common size is about 8 mm outer diameter, 5 mm inner diameter and 1.5 mm thick. Check that the listing says it fits Cherry MX-style stems.

What do 40A-L and 40A-R mean?

The number is hardness on the Shore A scale: 40A is softer, 50A firmer. On WASD rings, the L version reduces key travel by 0.2 mm and the R version by 0.4 mm. The figures describe travel reduction, not ring thickness.

Do O-rings change when a key registers?

Usually not when the ring fits correctly, because actuation occurs before the end of travel. Test the exact keycap and switch, especially with short-travel switches or thick rings.

Are O-rings or silent switches better?

They solve different problems. O-rings are cheap and reversible but only soften the bottom-out and shorten travel. Silent switches damp both the bottom-out and the upstroke inside the switch, but cost more. Neither fixes stabilizer rattle.

Do O-rings damage keycaps or switches?

They are removable, but check that the keycap seats properly and each key actuates and returns. Pull keycaps gently and straight up, especially on hot-swap boards.

How many O-rings do I need?

One per key: about 61 for a 60% board, 87 for a TKL and 104 for a full-size keyboard. Buy spares, as a few always go missing.

The bottom line

O-rings are worth a few dollars if the sharp bottom-out clack is what bothers you, and you don’t mind slightly shorter, softer presses. Start with a thin, low-reduction ring on a few keys. If your noise is rattle, ping or a hollow case, put the effort into stabilizer tuning, silent switches or foam instead.

Specifications reviewed against WASD’s O-ring guide and CHERRY’s switch explanation. Ring dimensions and effects vary by keycap and switch; check the exact set you buy.