... 4,High Quanlity&Reasonable Price vacuum tube solar water heater Certification:Have passed SRCC,CE,ISO9001:2000,CCC, solar Keymark ,SABS and other certificationFeatures:1 ... layer: 50-65mm imported polyurethane foam for superior heat preservation5) Specification of vacuum tube Absorption rate: ≥93%,thermal radiation rate:≤6% ... /76SP470-1800/58-304.323025026/63 colour steel vacuum tube solar water heater