JessEm Rout-R-Plate Phenolic Router Table Insert Plate, JessEm# 03101 3/8" thick phenolic with durable friction-free coating Convenient center-hole bushing used to align the router so it is centered in the bit hole Plate center-hole is machined to accept a 3-1/2" raised panel bit Two additional Tab-Loc insert rings to reduce the size of the bit opening Simple step-by-step instructions make accurately drilling and mounting any router easy