Ball shape. Available in a coarse grit. Shank is 1/4" in diameter. Overall length of the tool is 2 1/4". Manufactured for use in power drills and routers. Excellent choice for detail work on glass, stone, metal, ceramics, porcelain, and hardwoods. Manufactured in USA. 7/16" Diameter Ball $21.45 1/2" Diameter Ball $24.45 3/4" Diameter Ball $38.45 Thank you for visiting A&M Instruments, Tools and Machining. Please e-mail any suggestions or comments to improve the site, our service, or tool selection. Always wear proper eye protection and gloves when using any cutting or grinding tool. ALL diamond tools last longer if a lubricant or coolant is used during cutting or grinding. Copyright® 2002-2011 A&M Instruments Inc 770-772-6404