what you receive: you will receive 2 pieces bicycle police led lights, enough quantity for you to use and replace conveniently work effectively: our bicycle sound light can be applied as safety purposes while riding vehicle; the loud siren sound can draw people's attention on street and it can keep your kid from danger by warning or noticing others; there are 4 button to control kinds of sound, and the switch can control the flash modes give the effect of flicker; with 6 led design, it can give bright light easy to install: the bike sound light is easy to install and remove without tool; you just need to install 2 pieces aa batteries (batteries not included), then clip to seat post, insert the light and press the switch button durable material: our horn bicycle led light is made of plastic, which is durable, reliable and waterproof; it can be applied on rainy days, and it is powered by 2 aa batteries (batteries not included), can be applied for a long time wide application: our bike police led light can be applied for a wide range of activities: road biking, city commuting, bikes, kids bikes etc.; and it is very suitable for people who usually rides bikes at night