Ideal for sailboards, smaller dinghies, and lightly loaded control lines on boats of all sizes. Widely used in tractive effort of steel wire rope or other rope tools. The double pulley block fixed top for easy rope handling, smooth roller make the rope traverse unimpeded. Marine grade stainless steel 316 stainless steel. Strong durable reliable, anti-high temperature, heavy duty. Wheel width: 14mm, total length: 53mm. Max load: 661lbs(300kg). Design for hanging weight things to lighten load. Good use for sailboards, dinghies, boat, yacht, sailing, Kayak, etc. Note: The double pulley block can't 360°rotation.