SpeedTek RC 18,800uf 25V 2x2 capacitor pack can handle a maximum of 6s. It is proven to perform! We use these caps on all of or drag racing & speed run vehicles. They are also less than 2" square and use high flex/temp wire. 
 
The packs comes with an overall wire length of 4" and the option of terminating without a connector or a male/female XT90, EC5, XT60, Deans, Tamiya, EC3, or Traxxas connector.
 
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