1Lithium Ion Universal Charger: Compatible with 7V, 2V lithium ion rechargeable batteries. For example, 10440 14500 16340 16650 14650 18350 18500 18650 lithium li ion batteries. 2Security Protection: Undervoltage protection, overvoltage protection, overcurrent protection, over temperature protection, short circuit protection, battery reverse protection, zero volume battery repair, and excellent heat dissipation design. 34 Bay Smart Charger: 4 bay li ion battery charger can charge the battery separately. 4 bay can be adjusted according to different battery lengths. 4Compact and Portable: 4 bay 18650 battery charger is compact and convenient to carry, suitable for outdoor travel and emergency backup at home. 5Power Supply Method: USB plug power can be used for charging. 4 bay universal smart battery charger has stable and reliable performance.