Specifications Place of Origin: Shandong, China (Mainland) Brand Name: BTE&OEM Model Number: 58x2100mm Type: Vacuum Solar Collector Application: Water Heater Pipe Material: Glass Structure: Three Target Outer tube diameter: 58±0.7mm Inner tube diameter: 47±0.7mm Outer Tube thickness: 1.8±0.15mm Inner tube thickness: 1.8±0.15mm Tubes length: 2100±10mm Material of coating: Copper, Aluminum, Stainless Steel Coating: Three Targets Coating Absorptance: 0.92 Emittance: 0.06 Packaging & Delivery Packaging Details: 10PCS/Carton, 15PCS/Carton. Sample put in wooden case, Standard package carton for sea delivery. Delivery Detail: within 5 days after received part of deposit