Retractable Atlas S1D Feed Beam Machined S1D 14 Feet Aluminium Extruded Profiles Special Features 1. Material: Aluminum Alloy 7020 ; Heat treatment T6 2. Compliant with: GB/T6892-2006 3. Tolerance: twist degree--- less than 1degree per meter and 5 degrees for whole length; curvature--- less than 1mm per meter and 5mm for whole length 4. Mechanic: σb≥320MPa, σ0.2≥270MPa, δ5≥8% 5. The surface is free from manufacturing defects, such as nicks, dings, scratches . 6. Length Option