solar water heater:Outdoors, Mountaineering ,Fishing, Travels, Geology inspect, Field work. solar water heaterFunction: Heat waterSuitable for use: Outdoors, Mountaineering ,Fishing, ... into the groove of hinge, then put the cup in the sunshine, bottom towards to the sun, makes the ... Bottom diameter:10cm, Body diameter:8cmCup weight: 0.9kgAttention: Water must be added first before us, Do not use it ...