This kit will Convert any caliber Hornady new dimension sizing die (except 17 and 20) to Hornady threaded spindle design. Included in the kit is a threaded spindle and a threaded spindle collet. Specifications: - kit converts any caliber (except 17 and 20) Hornady new dimension sizing die to Hornady threaded spindle design. - kit consists of a threaded spindle and threaded spindle collet. - remove the non-threaded spindle, collet and expander ball from the existing die, install the threaded spindle and threaded collet, re-use the existing expander ball. - if the spindle on the expander die is already threaded, then this kit is not necessary. - all die sets shipped in 2006 and later are the new threaded style. - 17 and 20 caliber use zip spindle kit 550231