the connectors on those batteries are designed for helicopters.. I purchased a bunch of these from Hobby City and they came that way.. for car use I cut them off and put on Deans plugs... I'm not sure of the name of them, but EC3 sounds correct.. I think Losi is starting to use them now on some of their electric brushless stuff.. They work but you will have a harder time finding connectors for them at the LHS if needed...