... double hung window(W83A)1. profiles thickness: 1.6mm. 2. thermal break3. hardware: USA special hung hardware4. opening style: single hung ... . US design, succinctness line, single sash loading 75 kg, could make the big sash as require, overturn design, easer to clean6 ... wind loading performance.7. it suits for apartment and villa Thermal break Aluminum double hung windows(W83A)