The first unit had a small technical problem! After contact with the seller of the replacement was delivered in no time. Now I have tested the device on several missions. In the car with the Navi (Smartphone): No harassment of other passengers by the chatter of the announcer. Only the driver knows where to go !!! During Nordic Walking, also with a smartphone and an app Runtastic that pulse frequencies, distance and other details are whispered in his ear. Distances over 10 km are not a problem, because until now, the battery lasted a charging always longer than 3 hours For this price a real gem and therefore indispensable for me. I think also in the motorcycle helmet will provide his good offices.