This NSK Torque Type Attachment for the Espert 500 system is used with a ø1/4" chuck diameter with a special contoured hand-grip. • Collet Chuck Standard Size: ø1/4" (CHG-6.35) • Weight : 3.88 oz. • NSK Catalog Number: ES41552 Includes: • Collet Chuck ø1/4" (CHG-6.35): 1 pc. • Wrench (10 x 10) : 1 pc. • Bar Wrench (K-212) : 1 pc.