Don't let the small size fool you. The Original Incredibell is little, light and LOUD! Its diminutive dimensions and pivoting ringer let you mount it just about anywhere on your handlebars. A flick of your finger and the Ding! Ding! rings clear for all to hear. - Dome Diameter: 33mm (1.3") - Fits handlebars with 21.7mm - 26mm (.86" - 1.02") outside diameters