Types of Keycaps: Materials, Legends, Mounts, and Kits

Keycaps can be classified by five independent properties: profile (Cherry, OEM, SA, XDA, DSA), material (ABS, PBT, POM, polycarbonate, PVC, resin), legend method (doubleshot, dye-sublimation, pad printing, laser), stem mount (MX cross, Alps, Topre, Kailh Choc) and kit coverage. Stem and kit decide whether a set fits. The other three decide how it feels and wears.

These are separate properties: two sets made from the same plastic can use different printing methods and fit different keyboards.

Keycap types at a glance

Keycap profiles: the shape types

Keycap profiles come in two shape types. Sculpted profiles change angle or height row by row (SA, KAT, OEM, Cherry, MT3, DCS). Uniform profiles repeat one shape on every row (XDA, DSA, KAM, G20). Within each type, profiles differ by height and by the top surface: cylindrical, spherical or flat.

Das Keyboard’s profile overview lists these heights without naming the row or edge measured, so read them as a ranking rather than a clearance figure:

The keycap profile height chart keeps the measurement caveats, and keycap profiles explained covers row maps and typing feel. Cherry vs OEM and the SA profile deep-dive cover individual shapes.

Keycap materials: what the cap is molded from

Most keycaps are ABS or PBT. POM, polycarbonate and PVC are the other molded plastics, and artisans use cast resin. Deskthority’s keycap material reference is the source for the ageing and molding notes below.

• ABS. Smoother, slightly softer, holds bright colors and sharp doubleshot legends well. Its weakness is shine: the surface polishes where fingers land, developing a gloss over months of use. Higher-end ABS resists this longer than cheap ABS, but every ABS cap gets there eventually. It also yellows gradually under UV light, while its low mold shrinkage makes it the preferred doubleshot plastic.
• PBT. Denser and more heat-resistant, with a drier, slightly textured surface that resists shine far longer. It does not yellow under UV the way ABS does. It is harder to mold precisely, and demoulding shrinkage is why some PBT boards ship an ABS spacebar, so check product-specific molding, long-key straightness and spacebar material rather than treating the label as a quality certificate.
• POM. Slick, low-friction and self-lubricating, used occasionally for a distinctly smooth surface. It is denser than PBT and ABS, and its legends are usually laser-engraved.
• Polycarbonate. Transparent or translucent, used for shine-through and RGB-forward sets where light transmission matters more than texture. It does not yellow like ABS.
• PVC. Common on mass-market keyboards from brands such as Logitech, Dell and HP. It warps under high heat.
• Resin. Cast rather than molded, used for artisan caps, which are individual sculptures rather than sets.

The full comparison is in our PBT vs ABS guide, which also covers the cases where ABS is genuinely the better buy. Listings often credit the plastic or the wall thickness for a particular sound, but no controlled comparison is cited here, so this guide does not rank materials by sound. The keycap thickness and sound guide covers how to read wall-thickness specs and judge sound claims.

Legend types: how the characters got there

The legend method decides how long the characters survive and, on backlit boards, whether they glow at all. It matters more for durability than the plastic does.

• Doubleshot. Two plastics molded together so the legend is a solid piece of the cap rather than a coating. The character is not a surface ink layer, although the cap can still suffer physical damage. Glorious describes the process as molding two separate pieces of plastic, the body and the legend, together so the legend becomes part of the housing.
• Dye-sublimation. Dye diffused into the plastic under heat. Durable under ordinary use, common on PBT, and limited to legends darker than the cap unless it is reverse dye-sub, which prints the surround and leaves the legend in the base color.
• Pad printing. Ink applied to the finished surface, sometimes with a clear coat. Cheap, sharp when new, and the method most likely to wear away with use.
• Laser etching and laser engraving. These alter the surface rather than simply applying ink. Coatings and infill vary, so read the product description before assuming a particular construction.
• Blank. No legends at all, which sidesteps the whole question and removes a compatibility problem too, although widths, mounts, and the number of keys must still match.

Our legend methods comparison covers the trade-offs in full. If your board is backlit, the legend method and the plastic together decide what actually glows, which is the subject of the shine-through keycaps guide.

Types of keycap stems: whether the cap fits the switch

The keycap stem types in current use are the MX cross, Alps, Topre and Kailh Choc V1. The MX cross is the default: Cherry MX, MX clones and MX-stem low-profile switches such as Kailh Choc V2 all take it. Alps, Topre and Choc V1 each need caps made for that mount.

This is the axis that decides fit, and the one most listings gloss over. Signature Plastics’ family specifications identify mount as a separate property from profile: the socket must match the switch stem. Dimensions below are from Deskthority’s keycap mount reference: the MX cross figure is Cherry’s spec tolerance, while the same page gives the Alps peg as approximate.

The MX cross

Cherry introduced MX in 1983, per the Deskthority Cherry MX entry, which also notes the cross is only 180-degree rotationally symmetric, so standard caps do not always fit turned sideways. A cross-shaped appearance is useful evidence of mount type, but does not establish the fit of every switch and cap combination, so check the product’s compatibility notes as well as the shape. For MX-compatible alternatives, check the exact product family and revision; the clone-brand compatibility guide explains this buying check.

Low-profile stems: Choc V1, Choc V2 and KS-33

Kailh’s original Choc (PG1350) uses its own mount, which Deskthority says is inspired by Cherry ML but not compatible with it. Keebio’s low-profile guide confirms V1 caps and MX stems do not cross over, and lists MBK, MCC and DDC as V1-only sets. Choc V2 (PG1353), announced in March 2020, switched to an MX-compatible mount, as did Gateron’s KS-33 Low-Profile 2.0.

Two traps remain. Keebio notes that not every MX cap clears a low-profile housing, and Deskthority gives the Choc key unit as 18 × 17 mm against the standard 19.05 mm, so MX-sized caps can crowd each other on a Choc-spaced board.

Topre and Alps

Topre’s standard slider is not a cross. Deskthority’s Topre entry credits Cooler Master’s NovaTouch as the first Topre switch to take MX caps. hhkb.io notes those sliders were made from 2014 to 2016, and that among aftermarket MX sliders only Deskeys’ 2019 design supports spacebars and stabilized keys. Alps caps use a rectangular peg, and Deskthority stresses that not every Alps switch used this mount. Both are separate ecosystems with much smaller aftermarkets than MX.

How to identify your stem type

1. Find the exact switch model on the keyboard’s spec page. A brand such as Gateron or Kailh covers several mounts.
2. Pull one 1u cap. A plus-shaped cross means MX, a rectangular slot means Alps, and a low-profile switch without a cross is likely Choc V1. On a Topre board, assume Topre’s mount unless the listing says MX-compatible.
3. On a low-profile board, measure center to center between neighboring keys: about 19 mm is MX spacing, about 18 mm is Choc.
4. Match the result to the set’s stated compatibility, then run the kit checks below.

Getting the stem right is necessary but not sufficient, because a set with correct stems can still leave gaps. That is the next axis.

Size and kitting: whether the set covers your board

Keycaps are sized in units, where 1u is one standard alphanumeric key. The spacebar, shifts, enter and the bottom-row modifiers vary in width between boards, and a set that fits a full-size board can leave a 65 percent board with an unusable bottom row.

The parts of a listing to read carefully:

• Base kit versus extension kits. The base kit covers a standard layout. Extension kits add 40s support, ISO, spacebars, novelties or a numpad.
• Bottom-row widths. A 6.25u spacebar board and a 7u spacebar board need different pieces. Split spacebars and split backspaces need their own.
• ANSI versus ISO. ISO enter and the extra key next to left shift are frequently a separate kit.
• Row coverage on sculpted sets. A sculpted set has row-specific caps, so an unusual layout can need rows the base kit does not include.

Our kitting and coverage guide explains the unit system, and the compatibility guide walks the pre-purchase checks in order. Rather than doing it on paper, the kit fit checker takes your layout and the kits a set includes and returns the exact pieces you would be missing.

The special categories

Three product labels describe what is being sold rather than a particular plastic or mount.

Artisans are individually cast resin caps, usually 1u, sold as single sculptures rather than sets. They are bought for the object, not the coverage, and they have their own release culture of raffles and drops, covered in our artisan keycap ecosystem guide.

Novelties are the non-alphanumeric caps in a set: the decorated escape key, the themed enter, the extra modifiers. They are usually a separate kit and often the first thing to sell out.

Colorway kits are the same molds in different color arrangements. The language around base, alphas, modifiers, accents and sublegends is decoded in our colorway terminology guide, and it matters because “does the set include my modifiers in the right color” is a coverage question, not an aesthetic one.

How the axes interact

These buying checks interact with profile choice. A few relationships are worth carrying:

• Doubleshot pairs naturally with ABS, dye-sub with PBT. Not a rule, but it is what the market mostly produces, so a preference on one axis quietly narrows the other.
• Sculpted profiles make kitting harder. Uniform profiles remove row coverage from the list of things that can go wrong.
• Manufacturer determines availability more than preference does. Which profiles and colorways exist at all is set by a handful of producers, a landscape our GMK vs PBT keycaps guide maps.
• Price tracks the axes unevenly. Where the money genuinely changes the daily experience is the subject of our budget vs premium breakdown, and the best budget PBT sets guide shows what the lower end actually buys.

Specifying a set in one line

Once the axes are separate, a set can be described precisely enough to buy without surprises. A complete specification looks like this: profile, plastic, legend method, stem, and kit coverage for your layout. For example, Cherry profile, PBT, dye-sublimated, MX stem, base kit plus a 7u spacebar. To practice on real listings, run that spec against five Cherry-profile sets under $50.

If a listing does not let you fill in all five, that is the gap to ask about before ordering, not after.

The honest verdict

There is no single list of keycap types, because listings combine several independent properties and often highlight only one. Profile and material decide whether you enjoy the set. Stem and kit coverage decide whether you can use it. Legend method decides whether it still looks right in two years.

Start with coverage, because it is the only one that can make a set unusable, then choose profile for posture, material and legend method for longevity, and colorway last. When the set arrives, our safe installation and removal guide covers seating it without cracking a stem, and cleaning and care covers keeping it looking new.

FAQ

what is the most common type of keycap?

On mechanical keyboards, the most common type is an MX-stem cap, because Cherry MX and its many clones share the cross mount. By material, Deskthority’s keycap wiki treats ABS as the most common plastic, with PVC probably second on mass-market boards. Aftermarket sets are almost all ABS or PBT.

which keycap material is best?

PBT is the safest default for heavy daily typing: it resists shine and, unlike ABS, does not yellow under UV light. Doubleshot ABS is the pick for crisp legends and saturated colors, polycarbonate for backlighting, and POM for a slick, low-friction surface. No material fixes a wrong stem or a missing key.

do mx keycaps fit low profile switches?

They fit only low-profile switches with an MX-compatible stem, such as Kailh Choc V2 and Gateron KS-33 Low-Profile 2.0. Kailh Choc V1 uses its own mount and needs V1 caps such as MBK. Even with the right stem, check housing clearance and key pitch, because Kailh’s Choc unit is 18 × 17 mm, not 19.05 mm.

can you put mx keycaps on topre?

Not on a stock board. A Topre slider uses Topre’s own mount rather than a cross, so MX caps will not seat on a standard Realforce or HHKB. You need MX-compatible sliders, such as Cooler Master’s NovaTouch parts made from 2014 to 2016; among aftermarket sliders, hhkb.io lists only Deskeys’ design as supporting spacebars and stabilized keys.