The ANSI plate with Alps Stabilizers is cut from white 1.2mm Delrin (POM), while the Variable plate is cut from black 1.2mm Delrin.
B Stock options are available in limited quantities. 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.