For carbureted models. Requires two per bike. Easy installation in the fuel line about 4-6 inches before each carburetor. Unlike most filters that have paper filtration insert this one has pressed brass material instead that has minimal to no flow restriction. While in-tank screen on the fuel petcock will catch most foreign particles, it will let very vine particle pass through and make its way into the carburetor where it settles on the bottom of the float chamber and eventually start to cause performance and drivability issues.