THIS IS A ROHM KEYED BALL BEARING DRILL CHUCK, CATEGORIZED UNDER TOOLING & ACCESSORIES. THE CHUCK IS DESIGNATED BY THE PART NUMBER 215002 AND IS ENGINEERED WITH A 4JT CHUCK MOUNT. IT UTILIZES A JACOBS ARBOR CHUCK, SPECIFICALLY FEATURING THE 4MT/4JT CONFIGURATION. THE OPERATIONAL CAPACITY OF THIS CHUCK RANGES FROM 3/16 TO 3/4 INCHES, OR 1.5 TO 20 MILLIMETERS. IT INCLUDES THE REQUIRED K4 KEY.