K&N air filter for Yamaha Bolt. Dyno tested for 7HP (17% )increase in power with stock (ECU) fueling. It really wakes up the Bolt but there is an increase in intake/exhaust volume at higher throttle inputs. Comes with all installation instructions. Used last summer and then removed as I prefer the softer exhaust tone of the stock filter. If you're planning on a after market exhaust to go with this type of air filter you will also require a PowerCommander to re-flash the fueling maps. Fits all model years as well as the Café and Scrambler Bolts.