Teardrops n Tiny Travel Trailers

Does anyone have a propane or natural gas sniffer / alarm that they know works? I've been looking and reading reviews. Between finding units that eat batteries even though the battery is supposed to be only backup, units that don't alarm when a person can sniff the presence of gas, I don't feel comfortable about too many. Any comments about brands and models that folks are very pleased with would be appreciated.

I do a leak test every de-wintering soap and water and a mirror to see behind and since my gas alarm has never gone off