The Pulex MicroTiger Sleeve is designed with all the benefits of microfiber plus abrasive strips that line the strip washer, yet will not scratch glass. It presents two types of fibers plus a scrub pad on one end for stubborn dirt. The small white microfibers feature high water retention and work into pores to collect more dirt. A great sleeve built to last and for commercial window cleaning situations that needs a bit more scrubbing power.