The K&M Power Adapter and Shell Holder Retainer are used to neck turn under the power of an cordless screwdriver or low RPM drill. This kit Includes the the aluminum K&M handle if you prefer to go manual at times. The driver is a 1/4" hex standard shaft while the retainer utilizes Lee Auto Prime shell holders (not included) to hold the case. Neck turning or case prep under power greatly reduces the time it takes to get the job done! Shellholders Used: Lee Auto Prime