Great concept but unreliable
My first unit was also DOA, second worked fine for 11 months and then failed. It registered ok with the T6c watch but erratic / intermittent speed recording.The grooves for the battery cover are also a little flimsy - easy to strip off if you don't get it aligned just right.that said, the Suunto gear is great at recording data and providing feedback, just not so good at interval trainingCheers