Llambrich CY Plain Bearing Heavy Duty Threaded Mount K3 Keyed Drill Chuck, 1/2"-20 Mount, 2-1/16" Chuck Diameter, 1/64"-5/8" Capacity For stationary drilling, turning, milling and wood working machines The one piece ring and sleeve eliminates the possibility of the teeth breaking Hardened to avoid wear and lengthen the life of the drill chuck Machine fitting via JACOBS threaded mounts 1/64" - 5/8" Capacity