Description: Features: 100% brand new and high quality. Without 18650 battery,You need to prepare 4x 18650 or 26650 batteries yourself to use. DC 5.5x2.1mm interface has input and output functions,with DC adapter,easy to use. DC 5.5x2.1mm port for 16.8V devices USB 5V Port for Charging Smart phone GPS Tablet PC or 5V LED Light and more. Improve replacement battery pack inconvenient shortcomings,greatly facilitate the users of the battery pack DIY requirements,without spot welding battery,thereby greatly reducing the battery internal resistance,improve the battery discharge performance,so as to effectively improve battery life Power supply:you can use 18650 rechargeable lithium battery as a power source The output side:USB and DC dual output power supply function,DC output voltage is 16.8V(can power the 16.8V device,such as the bike light),USB output voltage is 5V(can power the cellphone and other 5V device),to meet a wider usage scenarios,the product comes with overcharge and over discharge protection,protection of the battery is more safe and sustainable Specification: Material:Plastic+metal Color:Black,Red Input Voltage:DC 16.8V Output Voltage: DC Port 16.8V Standby current Under 80A USB Output Voltage:DC 5V USB Output Current: 2000mA Size:9x6.5x6.5cm Cable length:29cm 18650 Batteries are not Included Note Please put in battery in a right way. Charge it when power indicator light flashes. Don't use the device in the water. Waterproof standard is IP67 Packing list: 1x Waterproof 4x 18650 /26650 battery box case.(without battery ) 1x 5.5x2.1mm adapter 4x 18650 to 26650 battery converter