... weather-resistance,heat-resistance,alkali-resistance4. Technical standard:Chinese high precision standard GB5237-20081. Alloy and Temper: 6061-T4 ... 6061-T6 6063-T5 6063-T62. Surface treatment.a). Mill finish, b). Polish, c ... ). Brush, d). Sand blasting , e). Anodized, f). Electrophoresis, g). Wooden gained, h). Powder coating, i). PVDF etc. standard ...