Double hung vinyl windows open and slide freely, soft sound, no dust off.  

Door and window frames, fan profiles are embedded with special steel lining.  

The glass should be flat and firmly installed. The installed glass does not directly contact the profile.  

Do not use glass glue.If double glass flat layer, there should be no dust and water vapor in the inter layer.  

Switch parts close tightly and switch flexibly.  

Model steel doors and Windows are processed with professional equipment in factory workshops, cannot be made in the construction site frame.