Anti-slip rubber bonded over cushioned foam is the build here, and the blue fleck in the rubber face gives a gym corner some character. Eighteen 24-inch squares at 0.55 inch thick click into 70 square feet, with 36 detachable borders for the outer run. The two layers are fused through an adhesive-infused bond, so the tiles hold together under a treadmill or a squat rack rather than separating along the seam. Impact from jump work is absorbed rather than passed into the joists, which keeps the noise down for anyone in the room below. Trim the perimeter tiles with scissors for a fitted edge, and expect the 30.5-pound set to sit flat over tile, marble, hardwood or carpet.