Increase battery capacity: Dual battery connection adapter allows parallel connection of two batteries, increasing the capacity and range of your electric bike. The switch manages the batteries in real time, automatically switching from battery to another when it runs out while driving. Smartly and balanced power your electric bike with the dual batteries simultaneously. and Practical: Made of aluminum alloy material, the adapter is and practical for long term use. Ensures reliable performance and efficient energy management for your electric bike. The positive and negative connectors should not be confused, and both batteries should have the same voltage. Before connecting, be sure to turn off the power to both batteries. Type:30A Colour:Black Material:Aluminum alloy Package Contents: 1 * Dual battery parallel module 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.