The Curve Ball X is a stationary foam roller (with firm foam) great at deep tissue muscle massage. This patent-pending inventive tool offers stable and controlled deep muscle massage. The grey, flat base is grippy, which means it won’t slide around. It stays in one place allowing for sustained traction on the muscle. The curved massage surface provides targeted muscle care and relief of minor muscle aches and soreness. Use your weight as leverage and let the tool do the work!