fuel filter band
oh also my fuel fitting didnt have an O ring on it.
The band is just there to hold the filter in place. Without it the filter can and may bounce around and slap on the underside of the car. Probably just a nuisance as a worst case scenerio - it is too far away to cause knock retard or anything - but I would imagine it would drive you crazy banging on the underside of the car.

