The Kuryakyn 9931 Bluegrass Breather Catch Tank features banjo fittings and chrome tubes that route the vented gasses upward so gravity can keep any expelled oil droplets in the engine. It is recommended to vent the crankcase in open air by running the vent line up and out of sight beneath the tank. Helps in venting expelled oil from the cylinder heads. Includes (1) Chrome Catch Tank Assembly, (1) Chrome - LIL Tank, (1) Chrome - LIL Tank Inlet Rib, (1) Rubber Gasket, (1) Vent Pipe, (1) Oil-Safe Sponge, (1) Hardware Kit; suggested for installation (not Included): allen wrenches. The Kuryakyn 9931 Bluegrass Breather Catch Tank is compatible with Harley-Davidson models: Using the Bluegrass Breather Kit.