The products are conformed to national technical standard GB/T3888-1999 for《aluminum alloy stainless steeI window hinges》. The heavy-duty friction stay hinge is applicable for large-scale hopper windows and sliding windows,e.g.PVC windows,large-frame aluminum aIloy windows and wooden frame windows. For heavy windows weighed above 32kg,heavy weight frictional stay hinge shall be used to meet safety demand and easily opening/closing,and provide enough force offrication when opening the window.