... /aluminium alloyBracket angle:0,18,22,38,45 optional, pitched roof, flat roof optional.Fastening pieces:Made of zinc-coated stainless steel..MODEL ... / 18 tubes/ 20 tubes/ 24 tubes/ 30 tubes Feature: Solar collector,solar energy collector,solar power collector,solar thermal collector.1. Manifold (interior)material: red copper2. Manifold (exterior ...