The popular Keller templates require the use of bits with shank-mounted pilot bearings., this bit is specifically designed for use in the Keller system., #45884, diameter (D) 5/8, angle (a°) 7°, cutting Height (B) 1, shank (D) 3/8, overall length (L) 2-5/8, type Dovetail, replacement bearing 47741, Keller number 2435, carbide Tipped Keller Dovetail 7 deg X 5/8 dia x 1 inch x 3/8 shank with upper Bb