Machined, chrome-plated brass guide bushes and chrome-plated steel guide plates. Ventilated guide bushes for optimised dust extraction. Includes 8 guide bushes (OD 5/16", 3/8", 7/16”, 1/2", 5/8", 51/64", 3/4" & 30mm) , alignment bush (porter cable adaptor) , table spacer and 2 x M4 screws.