This is the Traxxas Parallel Battery Connection Wire Harness. FEATURES: For use with Traxxas 2/3A battery packs only, with iD connector such as the Series 1 2925X 1200mAh NiMH battery, TRAC2920 Combines battery capacity for extra-long run time INCLUDES: Parallel Battery Connection Wire Harnesse with iD Connectors COMMENTS: Dual battery operation requires attention to precautions outlined in owner's manual. Follow all precautions to assure peak performance and reliability of model and batteries. jxs 03/21/16 ir/jxsBOX DIMENSIONS: 3.00" W. X .50" H. X 3.50" L.BOX WEIGHT: .05 LBS.