THE ITEM IS A SET OF JACOBS RUBBER FLEX COLLETS. THIS SPECIFIC TOOLING COMPONENT SET HAS A TOTAL CLAMPING RANGE SPANNING FROM 5/8IN TO 1-3/8IN. THE SET INCLUDES A COLLECTION OF INDIVIDUAL COLLET SIZES, SPECIFICALLY J915, J916, J917, J918, J919, AND J920, DESIGNED FOR VARIOUS TOOLING APPLICATIONS.