tower has the sirio evo 2 but with threaded shaft which is ok for the tc3, got one for my losi truck but it came with the small head, I think that the 3 port comes with the small head and the 5 port with the big head. sold it for 150 like brand new cause I wanted to purchase the sg shaft but it costs about 60, for that price plus a hundred I can get a new one 3 port legal with sg shaft