4 In 1 Car Digital Tire Pressure Gauge

4 in 1 car digital tire pressure gauge with emergency hammer led flashlight   feature: digital lcd display easy reading accurate and quick measuring maintain correct tire pressure reduce tire wear and extend tire life increase fuel efficiency improve vehicle handling and safety flashlight: use the flashlight in the event of a crash or night time gauge: digital tire gauge with led screen display emergency hammer: hammer can shatter glass in case of emergency seat belt cutter: built-in seatbelt cutter quickly slices through a locked seatbelt in the event of a car crash   specification: size: 16x8.5x4.3cmweight: 170gcolor: sliverbattery replacement: the unit is run by two different powersystems:1.the tire gauge is operated by a cr2032 3v lithium battery, included. The flashlight is operated by 2aaa 1.5v batteries, not included.2.there are two battery compartments in the back of the unit. The big one is for 2aaa 1.5v batteries. The small one is for 3v lithium battery.operating instructions:1. Press the switch with "gauge" mark to turn on the gauge. When the lcd screen shows "0.0" it means ready to measure the tire pressure.2. Place the nozzle of the gauge to the valve stem of the tire and hold tightly for one second, the remove the gauge from the tire you will read the accurate tire pressure from the lcd.3. When complete the measuring, you may turn off the switch by holding it for 2 seconds or leave it to be auto shut-off. The auto shut-off time is 30 or 90 seconds.