So the the top bit's the power source , yes ? .
Ah yes , that's the power source. Um.  going on to personal preferences , I've said that battery seems the best option for the actual remote , just because of the size. You don't want a a cable attached to the remote otherwise it's not it's not really a remote. Um and then the sender ,
and infra-red um has been used quite successfully. If the battery's on reasonable power , they always seem to work fairly well. You don't have to be point directly at the television itself.
So the battery is the  in the sender.