For all Mark 7 reloading presses - Revolution, Evolution, and Evolution PRO - this is a must have for your press caliber conversions. Use this holder to hold your spare tool heads nearby, with your dies and spare powder measure already installed. This will make your machine conversions a snap - just change your shell plate and other components, and then as a last step drop your spare toolhead (already configured with dies and powder measure) right onto your press. Align the press and you are now loading your secondary caliber. Made of high-grade aluminum, all CNC machined and polished to a high shine. Contains the Mark 7 logo.