The tanks are manufactured according to the European standards and are available in capacities from 500L to 2000L. They have up to two spiral heat exchangers which heat up the water in the main tank. Depending on the configuration the heat exchangers can be connected to the solar collectors, a burner (oil, pellet, wood, gas, etc.), in general, devices for closed water heating circuit. The tank also disposes sockets for temperature sensors, thermometers and electrical resistance.