DockShockle safely absorbs shock loads on smaller, lighter boats. DockShockle features a patented line limiter and progressive tension design to ease constant or sudden shock loads. It safely absorbs shock loads on smaller, lighter boats up to 40 ft. (12 m). DockShockle is made of 2500 lb. (1140 kg) test nylon webbing with an outer sheath of 3500 lb. (1590 kg) test tubular nylon webbing that's UV resistant to protect all internal parts. Webbing is 12" (31 cm) long. Ideal working slack in line is 3 to 6 inches (8-15 cm).