The Goji Smart Lock is similar in design and concept to the August Ring lock or Lockitron.
They are all wonderful smart locks but with one big disadvantage, they will not work on most standard locks in Europe. For a variety of reasons:
1. They are designed to be used with American deadbolt locks. American deadbolt locks are relatively simple tubular locks and only need to be turned about 90 degrees to close.
2. In Europe our mortise locks or multipoint locks require either 360 degree turns or 2x 360 degree turning. European locks (at least in NL, DE and I think BE). As such the motor configuration inside these smart locks need to be completely different (and heavier duty as European locks tend to have heavier springs and gears than in the US)
However, if you live in the USA, then the Goji certainly looks the best, out of the three that I looked at!
I saw a picture somewhere, it will run on 2x AA batteries.
Depending how power efficient it will handle the radio frequencies (bluetooth, wifi, nfc,...) the batteries will have to be replaced every few months or in best case, once a year