The system is installed directly over the prepped concrete. We also have flexible epoxy that can be used to prep wood subfloors. The Reflector Enhancer is a micro powder used in our clear 100% solids epoxies over a colored epoxy base coat. The first coat can be VB5 vapor barrier epoxy (over concrete) or flexible epoxy (over wood), or colored e100-PT4 100% solids epoxy (dark gray in this case). So the Reflector Enhancer coat is either the 2nd or the 3rd coat of the system, which can consist of 2-4 coats total, AUS-v urethane (no smell, water borne) being the most common choice for a topcoat.