SCSMR8/9BSK/WSMR8/9BSK Backstop Assembly Key Specs: - Box size: 8 / 9 - SCSMR / WSMR model: SCSMR8/9BSK/WSMR8/9BSK - SMR model: SMR8/9BSK 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