The X4™ 7700 is a premium performance unit featuring a new smart engine that raises the bar for refrigeration performance, efficiency and sustainability. Its Ultra-high capacity delivers our highest capacity along with fast pulldown, precise temperature control and peace of mind for the most demanding applications. The X4™ 7700 has ultra-high efficiency. Demonstrated 20% better fuel economy than its standard counterpart, thanks to the X4 7700 unit’s advanced smart engine. Common-rail fuel injection optimizes fuel delivery by 5% to 10%, and the engine’s new third “eco” speed adds significantly more fuel savings by reducing engine RPMs during intervals when conditions permit, improving operating efficiency over normal low-speed operation. Enhanced compliance. Reduced emissions that surpass EPA Tier 4, and lifetime compliant with California Air Resources Board (CARB) requirements without the need for future exhaust systems. Sustainability enhanced with R-452A, a refrigerant with lower global warming potential.