What's not to like?
I bought a few boxes of the P3 stems, and I'm a fan. These are the same material you'll find in Cobalts, Durock POMs, and Ultramarines, among others. I've been looking for a place to get them by themselves, and Wuque has delivered the goods. As a modular switch series, I think it's a genuinely cool idea. As a source of piecemeal components, I think it's fantastic. General info: UPE - as far as I can tell, these are umwipe - I believe "UPE" is just a shorter acronym in place of "UHMWPE" P3 - some kind of blend; not as soft as UHMWPE but still very slick (Durock POM, Cobalt, Ultramarine, etc.) LY - a more recent blend; seems more firm than the above - also nice and slick, but the Nebulas I tried them in have a fairly loose grip on caps POM - not sure what "modified" means, but these will be closest to a classic JWK linear stem; the vast majority of MX stems are made of POM