EZ Align Router Table Plate Centering System - Screw Size 5mm Your router plate should be the standard 1-3/8" recessed hole that accepts Porter Cable style bushing Screw Size M5 Fits ELU: 3304, Hitachi: TR12-M12V Makita: 3601-360; Ryobi: 150-151 This screw size may fit other routers not listed. Be sure to check your router base screw size