Cut from 1.2mm white delrin (POM). Fits all tray mount 60% and some other 60% keyboards.
B Stock options are available in limited quantities for all variants. These B Stock plates have kerf adjustments that are slightly too large, causing a significant portion of the switch holes to be .1 or .2 mm too small. The plates are perfectly usable with a little work -- any switch holes that are too tight can be shaved quickly into a usable size. A fraction of a mm of material will just need to be shaved from the top and bottom of the hole with a knife.