JR Connector attached to battery to allow use of Balancing Port on
A123 brand charger 
If you are ordering several batteries that that you would like balancers on,
please select the same number of balancing leads as batteries. A note in
the notes block during check out always helps as well.
NOTE:
Balancing 2S batteries is not a bad thing, however in low amperage service,
(all RX applications are considered low amperage application unless battery
system is undersized) balancing 2S is not necessary. Proper charging,
storage, and monitoring of 2S batteries negates the need for
balancing. Balancing Packs larger than 2S is always a good idea,
especially if in high amperage service.