E-z Change router bits are an economical alternative to standard router bits. They feature replaceable head carbide Tipped cutters, saving you money by replacing only the cutters when the knives become dull, instead of the entire tool. You wont need a second bit while yours is in the sharpening shop; instead, just change the cutters. You wont even lose your set-up because the E-Z Change cutters can be replaced with the bit in the router collet. The interlocking hex design guarantees that the cutting surfaces will not slip during use, #55178, 55178 3-pack REPL. Cutters (replaces ocemco ta-157)