Product weight: 880g (packing included Product size: 27x20x5cm How to use: 1. Start the engine and turn it at the normal operating temperature, turn off the engine and wait for the motor to stop, then remove all the ignition plugs. 2. Open the throttle butterfly completely and press the manometer connection head on the spark plug hole. 3. Use the engine to rotate the motor at a speed of 100-150r / min for 3 to 5 seconds, then the pointer on the instrument will go up gradually, it will stop when it reaches a certain value , and the value indicated at this time is the compression pressure of the cylinder. 4. Press the button once to return the pointer to zero. 5. Repeat the measured 2-3 times by following the steps above to improve the accuracy of the measurement. 6. General pressure of the car cylinders> 0.9 MPa, and