The RCBS Trim Pro case trimmer is a user friendly trimmer that provides very accurate, repeatable trim lengths time after time. By upgrading your Trim Pro with the Trim Pro-2 shell holder conversion reloaders will eliminate the need to purchase a new trimmer shellholder every time they want to trim a different caliber. This conversion features spring loaded jaws that accommodate cases with rim diameters from .250" to .626". Function: Upgrades original Trim Pro case trimmers to have the universal shellholder feature of the Trim Pro-2Notes: Cases with rim diameters larger than .625" must be trimmed in RCBS High Capacity Case Trimmer (Midway product# 175956)