BIKEMAN backpack allows cyclists to trigger variety displays including indicators， stop signal and even their own customized messages to remind particularly irritating drivers. It escorts your safety no matter in terrible weather or at night. Suitable for cycling at night， trekking， hiking， etc

Main Features:
Bag capacity: 5L
Frequency of wireless: 2.4GHZ
Controlling distance: 3m
Transmitter battery: 2 x CR2032
Transmitter shell material: ABS
Transmitter waterproof grade: IPX-5
Receiver battery: 3.7V， 600mAh lithium battery ( working for about 24 hours - full charged )