Make from stainless steel shell, coppers double grooves and nylon Wheel, enduring, wear resistant and assemble, stable structure, not easy to loosen, suitable for window with a slot width of 14mm / 0.55inch Double Wheel pulley design, with low frictions, stable operate, quiet and low noise, easy to push & pull It is fixed with stainless steel rivets, which is firm and none corrosive, and have strong bearing capacity Exquisites workmanship, high strength and resistance, Manufacturer: Zeizafa