Forster Products 028271: Quick-change Lower Shell Holder Jaws, is supported by spring-loaded jaws that contact the base of the cannelure for more positive extraction. The jaws are also self acting, so when a cartridge is placed in the die and the handle of the Co-Ax Press is activated, the jaws can open and close on the cartridge case. When the handle is raised, the jaws automatically open and release the case. This complete assembly contains everything you would need to easily swap out a single side of the S or LS Shell Holder Jaws, for all compatible cases, in any of the configurations listed below: S-Large holds .468 to .562 rim S-Small holds .343 to .422 rim LS-Large holds .531 to .625 rim LS-Small holds .312 to .375 rim