I understand that some folks who plan to use Tower as their FlightPower Eon F3A 5400 battery source have been waiting for Tower to list them as "Available" before placing an order. Be advised that the current Tower listing of "Back Order Only" means that Tower orders them from their supplier only after receiving a customer order. I don't know if Tower plans to stock the Eon F3A packs at some point, but the way to get them now is to place an order.