Spectators at this past weekend’s Tokyo Marathon may have noticed a couple of runners checking their splits on an unusual-looking device: a banana. Dole Japan used the race to debut a wearable banana watch, which is exactly what it sounds like. The gadget is basically a GPS device with an LED display that’s inserted into the peel of an actual banana. Runners can wear the banana around their wrists and—just like they would with a conventional watch—check their time, pace and heart rate, and even live-tweet their race. And yes, the banana is edible as well. Not surprisingly, according to Dole, this is the first edible product offering in wearable technology (sorry, Apple, your watch doesn’t count as fruit). The product seems to fit more with marketing than with actual utility, though, since Dole reports mass production is unlikely at this point. We’re betting that such a product would have a very short shelf life.