- Primary Accumulation and Domestic Hot Water
 - High density polyurethane isolation with stainless steel DHW accumulator
 - Capacities: 500 - 750 - 1000 L
 - 2 versions: with or without solar exchanger
 - BT DUO 500: Total volume (L) 505, DHW volume (L) 150, without solar exchanger
 - BT DUO 750: Total volume (L) 750, Volume DHW (L) 190, S / solar exchanger
 - BT DUO 1000: Total volume (L) 1000, Volume DHW (L) 190, S / solar exchanger
 - BT DUO 500 ME: Total volume (L) 505, DHW volume (L) 150, With solar exchanger
 - BT DUO 750 ME: Total volume (L) 750, DHW volume (L) 150, With solar exchanger
 - BT DUO 1000 ME: Total volume (L) 1000, DHW volume (L) 150, With solar exchanger