This Redding Bushing adapts 1"x14 tpi thread dies to 1-1/4"x12 tpi for use where needed. This is needed to use the new Redding Z Series Dies which are threaded 1" X 14 Threads Per Inch. This work on Hornady Single Stage Presses, Redding Big Boss II and Ultra Mag Press, and RCBS Rock Chucker, Summit and Rebel presses.