This is the bicycle alarm that automatically alerts a smartphone when it is stolen. The alarm looks like a typical bike light that attaches to the seat post and its built-in motion-sensor detects movement and instantly sends an alert to a smartphone via Bluetooth as well as sounding an audible alarm at the bike. The free app also allows you to drop a pin that maps where you last parked the bike so you can easily find your way back to it. When riding a bike, the alarm's light can be turned on to alert drivers to your whereabouts. The alarm can notify a smartphone up to 230' away and its rechargeable battery lasts up to two weeks after a two-hour charge via the included adapter. Compatible with iPhone SE, 6s, 6, 5, 4S, 4 running iOS 6.1 and up. 4 1/4" L x 3" W x 1 1/2" H. (8 oz.)