Heat exchanger principal traditional copper for ferroli wall gas boilers models:Arena F 13Arena F 16Arena F 20Arena F 24Divatop F 24Diva F 13Diva F 16Diva F 20Diva F 24Divaproject F 24Divatech D F24Divatech D HF24Divatech F 24 DDivatop HF 24Divatop Micro F 24