SCSMR6/7BSK/WSMR6/7BSK Backstop Assembly Key Specs: - Box size: 6 / 7 - SCSMR / WSMR model: SCSMR6/7BSK/WSMR6/7BSK - SMR model: SMR6/7BSK Features: - Easy mount for WorldWide shaft mount reducers - Smooth forward operation of conveyor with no backslip - Suitable for WorldWide Electric brand shaft mount reducers only