Features: Not need Welding :The 4pcs 3.7V 18650 rechargeable battery kit is with welding less design, which allows users to assemble it quickly without professional skills and saves time. Safe and Stable : The battery case supports the use of four 18650 batteries in series to ensure a stable power supply. Perfect for toys, LED lights and small electronic devices, ensuring safe and stable charging you use it. This rechargeable battery kit is compatibles most 18650 batteries on the market, both brand and capacity. The battery case with good abrasions resistance performances, and the service life is about 1.5 times higher than ordinary materials Specifications: Battery capacity: to 3.7Vx3400mahx4-50.32Wh Output power 16V5A, 7A, actual current is related to battery performances Output voltages: DC16V Output (unstable voltages, series voltages of 4 battery pack, 12-16.8V, related to battery capacity) Battery type: 3.7V cylindrical 18650 battery (recommended power battery) Charging type: 16.8V1A battery special charging Charging power: Input adapter power meets >=Total load power + 6watts of battery charging power; Protections circuit parameters: overcharge protections: 4.25Vx4; low voltages protections: 2.75Vx4; overcurrent detections voltages: 0.1V+-0.025V; Product size: about 93x85x25mm/3.66x3.35x0.98in Product weight: 102grams of empty box, 271grams of battery full Standard: DC5.5, 2.1mm (positive inside and negative outside) Package Includes: 1PC 4-cell series battery box note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.