Polybutylene terephthalate
Provided by the ASK Keyboard Dictionary
PBT is a plastic commonly used as a keycap material, amongst other things. Along with ABS, PBT is one of two main keycap materials and is known for being the higher quality material out of the two. PBT is more rigid and stays textured for longer than ABS, but is also more expensive and harder to mould. PBT also does not yellow when exposed to UV for a sustained period of time. PBT is famous for being the material IBM Model F and Model M buckling springs keycaps are made from.
