Seven models of the universal TR6 thermostatic expansion valve cover OEM air conditioner and heat pump designs in a wide range of applications, from 1.5 to 6 tons in R-22 and R-410A systems. According to the manufacturer, all aftermarket TR6 valves have 3/8- by 3/8-inch connections and come with Aeroquip and Chatleff fittings, meaning they easily install into almost any residential air conditioning system. This feature simplifies stocking and inventory, as service technicians do not need to carry several different OEM valve designs on their trucks and wholesalers can be assured that they will have a replacement TXV for OEM equipment, regardless of manufacturer. An internal check valve, adjustable superheat, and adaptable inlet and outlet ports make it easy for contractors to install the valve after selecting the refrigerant, tonnage, and connection type. Applications for the TR6 valves include replacement of a piston-type metering device for an efficiency upgrade and installation as part of a condensing unit replacement.