Get ready for unmatched power and convenience with the MagicShine USB rechargeable battery pack. Featuring 2*18650 batteries, this pack packs a punch with its impressive 2600mAh capacity at 7.2V, ensuring long-lasting performance for your MJ-900, 900S, and 900B bike lights. The 5.6x2.1mm round plug standard guarantees seamless compatibility. Whether you opt for the traditional A/C wall charger or the easy USB charging option, this battery pack has got you covered. With its IPX4 waterproof rating, it fearlessly tackles any weather conditions. Moreover, the removable battery cable can be effortlessly replaced with a waterproof silicon seal cap, enhancing its durability. Embark on your biking adventures with unwavering confidence, knowing you have a reliable power source at your fingertips.