air filter housing wing nut

It's kind of shocking to see how many people are running around without one, using string, bailing wire, duct tape. Without this, you'll never have the proper tension to hold down the air filter cover and you'll have a place for unfiltered air into the carb if you are using just a bolt. Splurge for the correct one. The winged part spins independent of the lower, rubber back grommet. 

OE part