The product consists of 4 single pulleys, two parallel pulley 2, two series pulley, 2 pulleys, 2 pulleys, two pulleys at the upper end diameter of 30mm, the diameter of the lower pulley 40mm, and the other pulley diameter 40mm. The pulley is made of high quality engineering plastics, the wheel shaft, the frame is made of metal, and the surface is plated with chromium, of which two and the pulley for the straight and four points of the straight side. One is open and the other pulley frames are straight and semi closed. The direction of the upper and lower hooks is 90 degrees each other.