1.Double stage coupling refrigeration cycle system design, a R410A/R515B system, two stage R134 /R515B system. 2.EVI DC inverter two stage heat pump. 3.Maximum outlet temperature 85℃/ 95℃. 4.Ambient temperature range: -35℃~43℃. 5.Unit modular design, multiple units in parallel to increase the total heat, centralized control. 6.4G DTU remote control unit.