This pack contains 10pcs of 1/4 (.2500). These micro drill bits are made of Tungsten Carbide. The over all length is 1.50". The shanks have a diameter of .1250 and all have identification rings on them. 10F2500$81.00 Call: 847-419-1267              Fax: 847-419-1241              Email: Drills2001@aol.com