Vented Gas Cap

Yes. Goes through the rubber cover around the filler, there is normally a hole right in the top of the frame rail. The tube simply ends, open ended, inside the frame.

This is an elegant, simple, system. You have to understand how it works. Because the vent is connected so high on the filler, this means the filler must be REALLY full to cause any siphon action out of the vent tube. And since the filler is tall and slender, this means maybe 1/2 cup of gas is all "worst case" you will siphon out. That is, unless it is very very full and you somehow parked with the filler pointed downhill at an extreme angle. Even then not much is likely to siphon.