Precautions for use and assembly: When welding battery leads/sampling points, be careful not to connect them incorrectly or in reverse. If a wrong connection is found, the circuit board may have been damaged and needs to be retested before it can be used again. During assembly, the should not directly contact the of the battery cell to avoid damaging it. The assembly should be firm and reliable. Electronic devices used for welding must be reliably grounded, and attention should be paid to electrostatic protection to prevent damage to the protective board caused by electric leakage and static electricity. Be careful not to touch the components on the circuit board with lead wires, soldering iron, etc. during use, otherwise it may burn out the circuit board. During use, attention should be paid to anti-static, moisture-proof, and waterproof measures. Advance notification(Very Important): (1) To use this product, you need to have some professional knowledge and experience. We do not that you can use it well. (2) You must have 18650 POWER li-ion batteries and the tools such as spot welding machines, soldering irons, multimeters, and suitable chargers, etc. (3) The PCBA label may not be exactly the same as shown in the following picture and may change with the batch. Please do not mind! Do not purchase if you mind. No-Original, , No Battery Cell !!!!!! Notes: After combining the battery pack and this protective board, if there is no voltage output during the initial power on, please activate it with a dedicated charger. Colour:As Shown Material:PCB Package Contents: 1 * Protection Board 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.