1.Circle top Sliding Aluminum window 2.better ventilation 3.High quality 6063 ... option5mm single glass, 12mm tempered glass, 5+6Argon+5 double glass, 5+0.76PVB+5 laminated glass, tinted glass, Low-E glass, reflective glassOur glass has AS ... 's able to use single glass or double glass in the system, according to customer's requirements. Project application Round top sliding aluminum window