... no water in vacuum tube. Heat quickly Competitive price CE,ISO9001:2008 Solar Keymark,SRCC certification this collector(SLB model) has a ... is used in big heating project,and split solar water heater system,or split solar heating system.Now it is popular with ... :Aluminium alloy,thickness:2.5mmDegree:20/25/30/38/45Heat pipe:red copper solar collector with heat pipe,aluminium solar collector