Standard valve guide (9 x 13.06 x 51.2 mm) fits intake and exhaust valves. Over time, valve guides wear out and fail to properly align the valve with the seat, leading to reduced engine performance from poor combustion sealing. Replace your valve guides when servicing valves or springs to maintain optimal function. This high-quality OEM replacement is sourced from Germany, guaranteeing precise fit and dependable performance. Sold individually.