Amana tool's fiberglass router (fgr) burs incorporate reciprocating diamond-fluted geometry, strong negative rake angles and generous Fluting to provide the best cutting action in a wide variety of woven resin BOND fiberglass and Composite Materials., #48012, (D) diameter 1/4, (b) Cutting height 1-1/8, (D) shank 1/4, overall length (L) 3, type end mill point, 48012 Solid Carbide medium burr with end mill point fiberglass and Composite cutting 1/4 dia x 1-1/8 x 1/4 shank router bit