Kilo Bike Super Loud Electronic Bicycle Horn Value Pack [Set of 5] Includes 5 super loud electronic bicycle horns (colors as shown in photos) Loud siren sound - Can surely draw people's attention on the street Easy installation 2 x AAA battery (not included) Size: 5 x 4.5 x 6.5 cm / 2 x 1.8 x 2.6 inch (L x W x H); Clamp Diameter: 2.1 cm / 0.8 inch