The battery clamp is made of excellent copper material to better conductivity and provide safety . After the automobile is started, the anti back charging current is less than 1A, the clamp is and more reliable. Connect the red clip with the black clip, there is no damage or spark when powered on, provides short circuit . The battery wire clip is made of excellent ABS plastic, with good insulation, resistance and aging resistance. The test wire clamp is used for emergency automobile start and battery booster cable, with strong practicability This battery clamp is made of high-quality copper, ABS plastic shell, and thickened silicone wire as raw materials. Therefore, it has good electrical conductivity, water resistance, and wears resistance performance. This battery clamp has a stable 12V voltage, it can supply power smoothly to protect the car . Notice: When Green light,forbid the short circuit or reverse connecting to car battery Cautions: Do remove the clamps in 30s after the vehicle started. Do not connect and/or attach two clamps together, it may cause danger! Keep this appliance away from children. Note: Installation guide not included, Please check as much as possible to make sure the item is what you need. Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Colour:Black Material:ABS Package Contents: 1 x Emergency Battery Jump Cable Clamps 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.