Bosch 13mm 1/2-Inch Keyed Chuck for Hammer Drills Specifically made for Hammer/Percussion drills. Rated for hammer drills up to 11 Amps/ 1100W Grips harder during hammering action. Fully sealed design for dust protection. Basic single direction (clockwise).Does not accept center reverse locking screw. Mount: 1/2"-20 UNF, Capacity: 1.5 mm - 13 mm, 1/16-in to 1/2-in Hardened steel jaws. Key is included (S2 style, Bosch PN 1607950045)