Reliable Power Source: Set of 4 rechargeable lithium polymer batteries with 1000mAh capacity and 3.7V voltage. Ideal for various devices such as MP3 players, Bluetooth earphones, GPS trackers, gaming consoles, smart watches, and more. Enhanced Safety Features: Equipped with a built-in protection circuit module to prevent overcharging and overcurrent. The included lanyard ensures easy handling without the need for connectors. Lead wire length: 50±3mm. Long-lasting Performance: These batteries offer leakage-free and cost-effective operation with extended service life. The PCM protection function safeguards against overcharging, over-discharging, overcurrent, short circuits, and overheating.