Since the introduction of PBS I was asked about low profile switch compatibility. While it would be easy to make a new stem for PBS the result would be less than ideal. A low profile keycap has to be crafted for low profile switches and that is exactly what PFF (Penguin Flat Feet) is.
If you are new here, PBS stands for Penguin Belly Slide. The name comes from the shape of the hitting area: soft, round and oblong. I always try to put ergonomics at the top of my priorities and I wanted to bring the same PBS smooth typing experience to PFF. That posed a series of challenges because of the limited space but also the lack of standard in the low profile world.
The top surface is indeed very close to PBS and that’s why we kept the “penguin” nomenclature in the profile name. Often low pro keyboards are released with laptop-like keycaps or anyway with very flat and squarish shapes with complete disregard for ergonomics. PFF is different, it’s hard to explain but I’m sure that as soon as you’ll try it, you’ll fall in love with it.
The hitting area is wide and inviting, the shape is cylindrical but the scoop is deep and round. Like PBS, PFF is uniform, you can mix and match keys wherever you want (DVORAK anyone?) and it’s an absolute custom/weird keyboards paradise.
So please don’t stop at how it looks, you really need to try it… Hopefully soon.
Manufacturing
Speaking of. Keyreative is the official manufacturer and they are doing an amazing job optimizing this challenging profile. The good news is that there are no intermediaries or exclusive vendors: anyone can order directly from them.
We already have a first round of prototypes and Zhao (keyreative) is busy completing the final tooling, if all goes well it should be ready by November 15 (crossing fingers). So the first set will be released at the beginning of 2026 and the good news is that it will be cheaper than PBS.
I don’t know yet what designs will be ready at launch, there’s a lot of interest from Japan, so JIS set is in the cards. If you have suggestions please let me know on Discord.
I’ve also heard that CannonKeys plans on releasing a low profile split keyboard that should feature PFF. That will be interesting to see.
Switch compatibility
While there’s some kind of standard in how the shape and connections of a cherry switch should be, for low profile it’s the wild wild west. And with such small tolerances it becomes complicated to design a keycap that supports them all.
Unfortunately we had to accept some compromises but I believe we ended up with something that should cover 90% of todays’ low-pro market.
We are still actively testing but the compatible switches should be:
- Cherry Low Profile
- Kailh Choc V2 (and other Kailh cherry-stem low-pro)
- Gateron Low Profile
- Huano Low Profile
It’s not easy to get hold on the Hauno switches but they are used in many of the low profile keyboards by Keychron which is a big player in this niche so we wanted to include it in the roster. You probably noticed the uniquely H-shaped stem of the Huano switch; if you look closely at the underside of PFF, you’ll notice the same shape mimicked at the top of the cylinder.
The keycap height is 5mm but the stem protrudes a little bringing it to 5.7mm. To make a comparison PBS is about 7.5mm but what matters is the PCB-to-Key-Top distance. A standard switch with PBS will stand approximately 17.8mm over your keyboard while PFF only 11.7mm (it varies depending of the switch). So even though the difference in height between the two profiles is only 1.8mm the actual keycap height if you had to use it on a keyboard is over 6mm. And PBS is a pretty short key to begin with. MTNU distance is 20.5mm bringing the difference with PFF to 8.8mm.
Here below a comparison with other keycaps but please note that PFF is still a prototype.
Going even shorter would mean getting rid of the ergonomic factor and possibly make the key thinner on the top surface. Both things I’m not prepared to do.
Material
PFF will be a composite of PBT with possibly fiberglass infill. The keys are pretty short and there’s not much material that can support the shape integrity during the cool down after the injection. The infill should help prevent warping but we are still experimenting with it. Fiberglass also gives better resistance to scratching which is a nice plus. The texture should be close to PBS, just one grade rougher but it’s hardly noticeable.
Of course PBT material also means that the legends will be dye sublimated, there’s no plan for doubleshot at the moment.
Supported keys
PFF is uniform, so all rows will be the same. That will make production simpler and keep the price down. All main key sizes are supported including a full convex bottom row.
The concave keys are: 1u, 1u homing (bar and deep-dish), 1.25u, 1.5u, 1.75u, 1.75u stepped, 2u, 2u vertical, 2.25u, 2.75u, ISO enter.
The convex keys: 1u, 1.25u, 1.5u, 1.75u, 2u, 2.25u, 2.75u, 3u, 4.5u, 6u, 6.25, 7u.
You can thank the JIS market for the 4.5u spacebar 😛.
That’s pretty much all for now, some details may still change but I’m extremely excited about how this project is coming out. I hope PFF will be welcomed by the community and I’m looking forward to testing it on more low profile keyboards, especially custom. In about a month I should have the final version in my hands so expect an update then.