Designed for bicycles and noticing they dont ride another lane, the button on the switch is a feline at any time, and when braking, on the road, a regular riders bike or car will change randomly, and it ignores the existence of the bike behind when encountered like road conditions.You can just stop giving them the way all the time.If you dont have brakes in time, accidents may happen. If so, the bike needs to alert the vehicle in front of the bike to warn the bike.Do not work with ordinary watches.