This Faithfull 4 Piece Router Bit Set is for use with kitchen worktop jigs. Tungsten carbide bits suitable for all routers with 1/2in collet. Contains: 3 x 1/2in Shank Straight: 12.7mm x 60mm, 12.7mm x 50mm(x2).1 x 1/4in Shank Flush Trim: 12.7mm x 25.4mm.