Nilfisk Advance 56384683 SC500 X20D Ecoflex A150 OBC PH Walk Behind Floor Scrubber with 140 Ah AGM batteries onboard charger and prolene brush. Benefits of SC500 Walk Behind Floor Scrubbers include innovative features and an easy to use ergonomic design. The SC500 ushers in a new wave of productivity equipped with SmartFlow Technology that measures how much solution should be dispensed and the EcoFlex System that determines how much detergent to mix into the solution.