... Years'Warranty 3.Delivery:7-20Days 4.OEM,2500Sets/Month vaccum tube solar water heaterInner tank:Food grade SUS304/2B stainless steel ... /135/144/162/180/216/270/288/306/324L.Vacuum tube:3.3 high borosilicate glass, 1.6mm thick absorption coating ... , Ø47mm or Ø58mm and length 1500or 1800mm, resisting 28mm hail.Tube quantity: 15, 18, 20, 24, 30, 32 and 36pcs.Heat ...