Nearly every keycap on earth is molded from one of two plastics. ABS (acrylonitrile butadiene styrene) is smooth, easy to mold in vivid colors, and softer. PBT (polybutylene terephthalate) is harder, dry and lightly textured, and famously resistant to wear. The internet has largely settled on "PBT good, ABS bad," which is a decent rule for $30 prebuilts and completely wrong at the high end, where GMK, the most coveted keycap maker in the hobby, molds exclusively in thick doubleshot ABS. The real story is more useful than the slogan.
The head-to-head
| Property | ABS | PBT |
|---|---|---|
| Feel | Smooth, can feel slick | Dry, lightly textured, matte |
| Shine over time | Develops greasy shine within months to years | Highly shine-resistant |
| Sound at equal thickness | Slightly higher-pitched, clackier, thinner | Deeper, more muted, thockier |
| Legends | Superb doubleshot crispness (GMK standard) | Excellent dye-sub; doubleshot PBT now common |
| Warping | Stable | Long caps like spacebars historically prone to warping |
| Typical price tier | Cheap on budget boards; GMK premium sets $110 to $180 | ePBT, Akko, PBTfans roughly $30 to $120 |
The thickness truth
Here is the fact that untangles most keycap arguments: thickness matters more than plastic type for sound. A thin 1 mm ABS cap from a budget prebuilt sounds hollow and high-pitched. A GMK-style thick ABS cap around 1.5 mm sounds full and satisfyingly clacky. Thick PBT at 1.4 to 1.6 mm sounds deepest and most muted of all. So when someone says their board got "so much thockier" after swapping to PBT, the jump from 1 mm walls to 1.5 mm walls did most of the work, and a thick ABS set would have transformed it too, just toward clack instead of thock. Cap height stacks on top of wall thickness: a tall profile like SA adds a resonant chamber that deepens and loudens everything, which is why thick-PBT tall caps are the deepest-sounding combination you can put on a board.
Legends: how the letters get there and whether they last
The plastic choice constrains how legends are made, and legends are where cheap caps go to die. Doubleshot molds the legend as a second piece of plastic running all the way through the cap: it can never wear off, edges are the crispest available, and translucent legend plastic enables clean RGB shine-through. Dye-sublimation diffuses dye into the surface, equally permanent, almost always on PBT, with one hard limit: the dye must be darker than the cap, so white-on-black needs the reverse dye-sub trick of dyeing the entire surrounding surface. Laser marking can look grey and fuzzy, and backlit budget caps usually laser-ablate a coating that wears through. Pad printing is ink sitting on the surface and is the reason your old gaming board has ghost-blank WASD keys. UV printing cures ink under UV and enables full-color novelty art with middling durability. If a set does not say doubleshot or dye-sub, assume the worst.
So which should you buy?
Buy thick, then buy the plastic that fits your priorities. If you hate maintenance and shine, thick PBT from ePBT, Akko or PBTfans is the sensible default, and budget PBT is one of the best value upgrades for a stock board wearing thin ABS. If you want maximum color saturation, the crispest legends, or a specific designer colorway, premium thick ABS is not a compromise, it is the top shelf; just accept that shine is eventually coming and some people even like the polished look. Check spacebars in reviews if you go PBT, since long PBT caps historically warp. Then pair the caps with the rest of the sound chain: the switch, the plate and the foam situation all gate what the caps can do. You can hear how much the cap layer shifts a note by playing any switch in the simulator, where thick-cap acoustics inform the sound model, or compare deep-voiced switches like the Oil King against bright ones like the Alpaca to know which direction you even want the caps to push.
Frequently asked questions
Is PBT better than ABS?
PBT resists shine and has a dry matte texture, which makes it the better low-maintenance plastic. But ABS is not the budget option people assume: the most expensive keycaps in the hobby, GMK sets, are thick doubleshot ABS. Thickness and manufacturing quality matter more than which plastic is molded.
Why do ABS keycaps get shiny?
ABS is a softer plastic whose textured surface polishes smooth under finger oils and friction, developing a greasy-looking shine within months to a few years depending on use. PBT is harder and highly shine-resistant, keeping its matte texture for many years.
Do ABS and PBT keycaps sound different?
At equal thickness, ABS sounds slightly higher-pitched and clackier while PBT sounds deeper and more muted. But thickness dominates: thin 1 mm ABS sounds hollow and high, thick GMK-style ABS around 1.5 mm sounds full and clacky, and thick PBT at 1.4 to 1.6 mm sounds deepest of all.
What are doubleshot and dye-sub legends?
Doubleshot molds the legend as a second plastic passing through the cap, so it can never wear off and allows crisp shine-through for RGB. Dye-sublimation thermally diffuses dye into the plastic surface, also permanent, but the dye must be darker than the cap, so classic dye-sub cannot do white legends on black caps without the reverse dye-sub technique.
Keep learning
- Keycap profiles explained: height and shape, the other half of the keycap decision.
- Thock vs clack: where cap plastic sits in the sound chain.
- Keyboard builder: try colorways on a full board before buying a set.
- Case foam: the mod that decides how much your caps can shine acoustically.