I bought the Att dongles to go onto my Delkims years ago, must be 10+?
I'm sure I had them when I first went onto Nazeing in 2008, so they have lasted. The receiver lasts at least a year on a single Eveready or Duracell AA battery, however dependant on use or type the dongle batteries will need changing around every 3 months. The GP batteries don't have a good life, the ones I got from Maplin were a whole lot better, sadly Maplin๐
I know this goes against Emmcees opinion, sorry, I have found the ST Delkims with the dongles worked for me, and I know it is a common judgement that Delkim TXi's had water ingress problems for a few years.