9" Gel Drive Hook & Loop Plate for OFEDGE S-4 (2 per pack). The drive system in the OFEDGE S-4 will undoubtedly feel better with these 2 sets of replacement kits. If your OFEDGE S-4 machine needs a replacement gel drive hook & loop pad, Onfloor technologies have the best kit to keep it going. Using other traditional gel drive hook & loop pad would not last as long as the ones from the Onfloor Technologies stores, and it will definitely give a low output while using them on your concrete floor.