Black nylon plastic with a matte finish and slight grainy feel.
About this Product
Replacement part 151 for a Porter Cable 557 type 1 biscuit joiner. This part is no longer available from part suppliers, but now you can print your own and fix that otherwise-unfixable tool.
May work with type 2 as well, but this hasn't been tested. I should stress that this will probably NOT work with type 3 or type 4 (but then, the replacement part is still available for those types.)