The Lee Precision Auto Prime Shell Holders uses standard shell holders and will fit any brand of loading press with a vertical ram. Primes are on upstroke for most sensitive feel. Includes primer feeders and punches for both large and small primers. Primer tray detaches for filling. Primers are flipped right side up by shaking the tray. The Lee Precision Auto Prime Shell Holder Set comes with a red storage box and 11 shell holders for the Lee Auto-Prime.