Oi Prima bike bell features our signature wrap-around bell design and our newest innovation - WAVETEK hammer technology. The whip of this new hammer design helps to create a beautiful and consistent bell tone, while being built for robust and long-lasting use. Available in two sizes to ensure the correct fit on your handlebar (see our size guide for info on how to measure your bar diameter). FEATURES Our signature wrap-around design. WAVETEK - the latest in bell technology. Built to last with a robust spring design. Beautiful tone that's loud but pleasant. Available in two sizes for a perfect fit (see below). SIZING Small Oi Prima for 22.2mm handlebars diameter. Large Oi Prima for 23.8 - 31.8mm* handlebar diameters. *Shims / Spacers included with all Large size bells for the perfect bar fit. Consult our size guide for more information. WHAT'S IN THE BOX Oi Prima Bell Hex Key Shims - Spacers for the perfect bar fit. Large size bells only.