Round Under Router Bits 2 Flute With Ultra Glide" Radius Bearing .1" Material,1/2" Radius, 2-1/8" Large Diameter, 1/2" Shank, 2-7/8" OAL. Application: Use with corner rounding bits, to cut a full 180° bull-nose on 1/2", 1", 1-1/2" or 2" thick stock without turning the material over. (Two 30"x98"x1/2" laminated sheets = 200 lbs. +). Also useful for 'on-site' cutting where a conventional round-over cannot be used. Furnished with Ultra-Glide" non-marring Delrin® sleeved ball bearing guide. Replacement 'Ultra-Guide"' bearing #47737 (after 6/95). Replacement steel bearing #47738 (prior to 6/95). Replacement collar #47740.