Double battery controller for switching parallel batteries to increase capacity. The dual battery pack switcher can manage two battery packs fixed on the bicycle, with low power consumption and power consumption design, and can detect the voltage of two battery packs in real time and check the batteries online. When one battery runs out when riding, it automatically switch to another battery pack to supply power to the bicycle again. When the voltage is lower than the low cut-off voltage, the module stop the power output to protect the battery. Colour:black Material:Aluminum Alloy Package Contents: 1 * Double battery controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.