The Knee RX HD Kneeling Mat was designed for extreme kneeling applications such as gravel, asphalt, concrete, tile, and wood flooring, providing ergonomic support by reducing trauma, stress and strain on the knees and lower back. The 951 HD version offers a durable heavy-duty rubber bottom surface for long-lasting wear in the roughest environments. The Knee RX HD provides a comfortable work surface for those who are required to occasionally kneel while working and eliminates the hassle and discomfort of wearing knee pads.