Features: Car audio speaker test phasemeter, can be used for troubleshooting and testing audio systems, effectively testing speaker polarity. Made of high quality ABS shell material, durable and reliable, with long service life. Exquisite craftsmanship, excellent durability and practicality. Shipping with 6F22 battery, with indicate light, yellow light on indicates that the battery power is low. Widely used to test almost all speakers of cars, such as small treble, door speakers, subwoofers and more. Package Includes: 1 Piece Phase Tester 1 Piece Disc 1 Piece Battery Specifications: Product Name: Phase Tester Model: FH-168 Material: ABS+Electronics Battery Type: Lithium battery Battery Model: 6F22 9V battery(shipping with battery) Applicable Car Models: Universal Application: The loudspeaker wiring specially for adjusting the car sound system note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.