Designed for a wide variety of applications. Each router bit is manufactured from amana’s exclusive grade carbide according to stringent quality standards, #AMS-149, (D) shank: 1/4, AMS-149 3-pc solid carbide Up-cut spiral ball nose CNC router bit Pack, 1/4 inch Shank, includes 1/8, 3/16 & 1/4 diameters