The Small Knog Oi Bicycle Bell fits 22.2mm bars e.g Mountain bike (near the grips), BMX & some old commuters. The Large Oi fits 23.8 to 31.8mm bars e.g. drop bar road bikes and some cruiser/commuters. Please make sure you know where on your handlebar you are going to place the bell (grips or stem) before you order as you may need a different sized bell.
