CMT 661.031.41 Roundover Bits w/Insert Knives 1/2" x 1/8" (R=1/8") S=1/4"The CMT 661. 031. 41 is a 1 2 inch roundover router bit with two replaceable insert knives (R=1 8 inch) and 1 4 inch shank. Features a 4 sided knife insert that can be rotated for 4 usable cutting edges. For rounding over edges on hardwood, softwood, laminates, and chipboard. Bearing guide for accurate edge following. SPECIFICATIONS Order Number 661. 031. 41 Cutting Diameter 1 2" Radius (R) 1 8" Cutting Length (I) 1 8" Shank Diameter 1 4" Overall