Mastercool 98063-BT Sensor: Glass bead thermistor with temperature compensationConnection Fitting: 1/4 SAE F-FL with stem depressorOperating Temperature: 32 to 120°F (0 to 45°C)Accuracy: ±10% of reading (from 10,000 to 100 microns)Proof Pressure: 450 psi Digital Vacuum Gauge with Bluetooth Wireless Communication Compact hand-held digital vacuum gauge with Bluetooth wireless technology which combines the most advanced features to provide quick and accurate responses every time. Utilizing a state-of-the-art glass beaded thermistor and temperature compensation, Mastercool is offering the latest technology to the HVAC/R technician.Included in this package will be the capability to download Mastercool's free app. This will allow for full mobility as activity will be easily viewed on all compatible hand-held smart devices.