Porter Cable 42950 - 1/2 inch Router Collet. Use as a replacement collet or to adapt a router for use with 1/2-inch shank bits. This collet fits Porter Cable router models 690, 9690, 691, 693, 693PK, 7529, 97529, 7518, 7519, 7538, and 7539. It has an auto-release design which keeps the collet captive in the collet nut so the collet is automatically released from the arbor as the collet nut is loosened. The router bit, collet, and collet nut are removed as a unit to prevent "frozen" or stuck router bits. Includes one collet and collet nut assembly.