nylon straps/plastic double gates. Set so you can tighten them and loosen them while riding. Probably works just as good/better than most expensive set and forget methods. This is just my opinion after riding this setup for about a week... sooo yeah. Idk, I would say just buy a $10 set up see how it works for you, if you want to upgrade get the exhausters(wabi cycles) people seem to like them.