The Kuryakyn 9977 breather hose provides a replacement piece for your motorcycle crankcase breather hose. Using the breather hose you can install new or replacement breather components, allowing you to maintain your motorcycle condition. Durable designed for optimum performance. Includes (2) formed breather hoses; suggested for installation (not included): original breather hose instruction manual. The Kuryakyn 9977 breather hose is compatible with Harley-Davidson models: '99-'17 Twin Cams.