FloorLyft Ultra underlayment panels (model FLY6ULTRA) provide a rigid, stable subfloor base for floating floor installations including laminate, LVP, and engineered hardwood. Each panel measures 2' wide x 3' long x 6mm thick. This set covers 90 square feet total. Designed to bridge minor subfloor imperfections, reduce sound transmission, and provide thermal insulation. Like-new condition, in original packaging. No damage or missing pieces reported.