theorytically it can achieve constant speed 42Mbps and can go until max 300Mbps if you are using LTE.
but of course, it is TM product. you will not get that speed. it says in their brochure, the speed is not capped.
it also depend on what actual max speed the the tower and you phone transceiver can push. also it depend on what speed that TM actually capped but advertised it as "unlimited speed" hihihi.