1, Three layers vacuum tube 2, Copper heat pipes built in 3, Rock woll insulation 4, SRCC,Solar ... Keymark,CE,ISO red Solar Collector With Heat Pipe 1. Spcification of solar collector out casing: aluminium alloy ... tube: 58*1800mm, ALN/AIN-SS/CU 1.6mm thickness heat pipe: red copper, anti-frizen, 1700mm length frame: aluminium alloy ...