When I lived in Greenbrier, bought a 75 gallon so I could fill my whirlpool tub in the master bedroom. Name of it slips my mind. They said anything larger would require installing a larger gas vent through the roof. Sold that house and moved cross country to Vegasland.
Now I remember, bought the water heater from Nashville Gas Company and they installed it also.They had a deal where if you couldn't pay cash they would put the payments on the gas bill.