The VTA/N "Tank in Tank" buffer tank features a stainless steel tank inside a carbon steel tank. This design combines the benefits of both a storage tank and a heat accumulator, allowing for simultaneous use in heating systems and hot water storage.

The inner tank is made from high-quality food-grade stainless steel with a wave-shaped wall for increased resistance to pressure, improved heat exchange area, and self-cleaning through thermal expansion.

The VTA/N-1 model includes a carbon steel heat exchanger at the bottom for optional connection to solar systems or other heat sources (heat pump, gas, solid fuel, electric boilers).

The VTA/N-1-SOLAR PLUS model has an enlarged inner tank partially placed within the heat exchanger, improving efficiency with low-temperature heat sources.

The VTA/N-2 model lacks a heat exchanger, allowing direct connection to any heat generator.