The YELLOW JACKET® ManTooth™ wireless digital pressure/temperature gauge provides wireless connection to your smart device so you can test the system without losing refrigerant (no hoses or manifolds necessary).The free downloadable ManTooth RSA app wirelessly calculates and displays the system's actual pressures, temperatures, superheat and subcooling in an easy-to-read color format on your iPhone®, iPad® or Android™ device. Yellow Jacket® ManTooth™ Dual Pressure Gauge Set, -4 to 160 deg F Ambient Operating, Battery Power Source