THIS IS A NIKKEN COLLET CHUCK TOOL HOLDER WITH A CAT 40 HOLDER TYPE. THE TOOL HOLDER'S DIMENSIONS INCLUDE A BORE HOLE DIAMETER OF 15MM, A MAXIMUM BODY DIAMETER OF 43.8MM, AND A MINIMUM BODY DIAMETER OF 22MM. THE PROJECTION MEASURES 5-5/8 INCHES, AND THE OVERALL LENGTH WITHOUT THE BUTTON IS 8-1/4 INCHES.