Being that the radions are up to gen5 now, I'm guessing those are used? As to how long they will last - that depends on how hard you push them and several other factors so it's a difficult question to answer, but I have a pair of AI Sol blues that are about 8, a pair of kessil A360W's that are about 6, and a pair of radion XR30G4 pros that are about 1 1/2. All are going strong, but I max them out at about 70%.