RPM-V1 Radiant Positioning Mats (RPM) 20" x 44" Installs directly over plywood or concrete Cuts quickly and easily using a razor blade to score and snap Stud spacing configured to allow the cable to be installed at 2in., 2.5in., 3in. or any desired spacing Rubber grommets keep the cable in place during install and allows for a quick installation or re-positioning of the heat cable (sold separately) A cement leveling material is poured into the RPM mats and the top of the studs are used as the screeding surface.