1) Intelligent control: Micro processor based digital controller with LCD display. 2) Durable-more than 15 year's life time. 3) Adjustable water temperature setting: 25-85. 4) EVI Scroll compressor specially designed for high water temperature heat pump. 5) ECO-friendly refrigerant R134a. 6) High efficiency tube-in- shell water heat exchanger. 7) Easy installation and operation. Optional: Direct heating / Circulation heating type Titanium Tube Heat Exchanger / stainless Steel Heat Exchanger R410a, R22, R407c refrigerant is available.