Bike bells generally look & sound a bit ugly. But why? What if they looked sexy & sounded like an angel playing a glockenspiel?
 
The bells fit on almost all cylindrical bars. The Small Oi is best for the common 22.2mm bar, and with the "spacers" that come in the pack, the Large Oi is for all bar sizes up to 31.8mm. The Oi will also work on any aero bar with a 16mm cylindrical section (usually near the stem).

 
SPECIFICATIONS
SIZE: Small bell fits bars 22.2mm diameter // Large bell fits bars 23.8mm - 31.8mm (How to measure your handlebars).

WEIGHT: 18g

MATERIALS: Aluminium with Nylon mount & acctuator

BIKE ATTACHMENT: Nylon clamp with hex screw to secure bell to your bike. What about getting it on the bar? Just pop it over, give it a quick tighten up, and you're good to go. No sliding down the handlebars, no dismantling and re-assembling.

CABLE MANAGEMENT: Built into the shape of the Oi mount is a cable management system. So not only does it allow the bell to look and sound uninterrupted, it also helps gather your cables (for the organiser inside us all)