This is the Castle Creations Parallel Battery Wire Harness with Deans Plugs. FEATURES Connects two battery packs in parallel, enabling capacity (mAh) to be doubled while the voltage stays the same 10 gauge wires RoHS compliant INCLUDES Parallel Battery Wire Harness with two Deans Male Ultra Plugs and one Deans Ultra Female Plug SPECIFICATIONS Length: 5.5" (140mm) not including connectors COMMENTS Always use identically prepared packs with this harness. Both packs must be fully charged and properly balanced. Both packs must be made by the same manufacturer, have the same C rating, same number of cells, and both must have the same capacity. Failure to observe this warning will result in battery damage.