... .Adopts world famous parts 3.On line system 4.R410a Air Source heat pumpModel: AW09,AW09B,AW10,AW10B,AW12,AW12B,AW13,AW13B ... ,AW15,AW15B,AW20,AW20BLow temperature air to water heat pump :AW10/L,AW13/LNormal air to water heat pump can work at above ... -10 degrees ,Low temperature air to water heat pump can work at -20 degrees.AW09,AW09B,AW12,AW12B ...