The 4.0mm Banana Plug to T Plug Adapter will let you connect a battery with a T Plug to an ESC that has a Redcat Racing 4.0mm Banana Plug connector on it.

Redcat Racing has introduced a new banana plug connector on most of their electric rc trucks starting in 2011. As of October 2011, the remaining exceptions to this were the Sumo trucks, truggies, and crawlers; the Ground Pounder; and the Twisters.