This charging lead / charging adapter is what you need if you are wanting to connect your 1st gen 2S E-flite UMX model batteries to a smart balance charger.
This will split the all in one balance and charge plug found on the battery into a separate power plug and balance plug allowing you to use all the functions of your smart charger on these packs, looking after them and extending their usable lives, especially balance charging and storage charging.
Perfect for the batteries you use in the new Micro Apprentice STOL and all the classic UMX models.