... 2.heat insulation 3.watertightness, windtightness,airtightness aluminum windows:1.frame material: upvc\pvc\palstic\aluminum\aluminum alloy.etc2 ... and easy to install2.security3.windtightness, watertightness, airtightness, thermal break, noise insulate, lighting. WIND RESISTANCE3.5≤P3<4.0WATERTIGHT ... 0.5(m3/m·h), q2≤1.5(m3/m2·h)THERMAL BREAKK<1.5NOISE INSULATERw≥45LIGHTING PERFORMANCETr≥0.60 ...