Product Introduction: 1. Battery Tester Is An Application Assistant Specially Designed For Car Battery Batteries. This Is A Practical App, Users Can Check The Real-Time Voltage Of The Car Battery And Other Related Information Through The Mobile Phone In Real Time. 2. It Can Monitor The Voltage Of The Car Starting System And Charging System In Real Time, Helping Users To Fully Understand The Data And Characteristics Of The Car Battery. 3. Transfer The Data To The Mobile Phone Via Bluetooth, And Enter The App To View It In Real Time. Android Operation : Open The Mobile Phone Settings-Bluetooth-Select Pairing -App, Enter The App After The Connection Is Successful, Click The Setting In The Right Corner, Find The -App In The Device Management To Connect, And Test After The Connection Is Successful. Ios Operation : Open The Mobile Phone Settings - After Confirming That The Bluetooth Is Turned On, Go Directly To The App And Click The Setting In The Right Corner, Find The -App In The Device Management To Connect, And Test After The Connection Is Successful. Install The Red End On The Positive Pole Of The Battery Install The Black End On The Negative Pole Of The Battery Product Parameters Name: Automobile Battery Tester Working Voltage: 6V-18V Working Temperature: -40-60 Material: ABS colour: Black Package Contents: 1 Set x Automobile Battery Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.