Don't let the small size fool you. Mirrycle's Incredibell Triple is little, light and LOUD! Plus, its diminutive dimensions 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. The Triple fits the 3 most common handlebar sizes: 22.2mm, 25.4mm and 31.8mm. - Dome Diameter: 37mm (1.3")