THIS IS A DORIAN TOOL 881 QUICK INDEXING TOOLHOLDER, CATEGORIZED AS TOOLING AND ACCESSORIES FOR LATHE OPERATIONS. THE ASSEMBLY INCLUDES A SPECIFIC INTERNAL THREADING BAR CARTRIDGE, IDENTIFIED BY THE DORIAN TOOL PART NUMBER NL75R. THE PHYSICAL DIMENSIONS OF THE QUICK INDEXING TOOL HOLDER ARE 3-1/2 INCHES WIDE, 1-1/2 INCHES DEEP, AND 2-1/8 INCHES IN HEIGHT. THE ASSEMBLY ALSO INCORPORATES A 2-1/4 INCH WEDGE COMPONENT.