2005 hyundai tucson battery drains. We're almost positive it's the radio. What radio can we get to replace it and fix the problem

Get any after market you want. Buy the kit to install it in your car. If you go factory from a junk yard. You make have to have it programmed at a dealer.

Unless the radio is defective, or, in the case of an aftermarket radio, wired incorrectly, there is no reason for a radio to cause a major battery drain. Yes, they do have a constant source to maintain memory, but that current is minimal. Any radio, operating properly and installed correctly (meaning that the main power is on a switched circuit that goes off with the ignition switch) should be fine.