This is the Series 10 Gauge Wire Harness from Castle Creations. FEATURES: Connects two battery packs in series enabling the voltage to be doubled YOU WILL RECEIVE: Series 10 Gauge Wire Harness with two Deans male plugs and one Deans female plug REQUIREMENTS: Connecting to batteries and electronic speed control SPECIFICATIONS: Wire Length Between Connectors: 5" (127mm) Wire Size: 10 gauge COMMENTS: Use only identically prepared packs with this harness. Both packs must be fully charged and properly balanced. Both packs must be from the same manufacturer, have the same C rating, capacity and level of charge at all times. Failure to observe this warning will result in battery damage. jxs 10/15/09