K&N universal air filters come in four styles
round straight, round tapered, oval straight and oval tapered
All round straight types, oval straight types and oval tapered types have rubber end caps (unless noted differently)
All round tapered types have chrome end caps (unless noted differently)
All clamp directly to the carburetor throat, replacing the stock airbox and filter element
Pleated design increases surface area air flow
Match the outer diameter (o.d.) of your carb throat with the inner diameter (i.d.) of the filter (given in inches and millimeters)
Video presentation for air filter clmp on 89mm