Working on an old Yamaha two-stroke or classic bike? This is a pack of 10 fuel petcock gaskets. The part number is 137-24523-00, and they're brand new from Ottoclassic, but made to the original Yamaha spec. They fit a ton of vintage Yamaha models: DT125, DT175, YA6, YAS1, YCS1, YL1, YL2, YR1, YR2, XS1, XS2, DS7, and probably others. The petcock is the fuel shut-off valve on your gas tank, and this small gasket seals it to prevent leaks. On old bikes, these gaskets dry out, crack, and leak fuel – a common issue. Having a 10-pack is brilliant because you can replace them on multiple bikes or have spares for the future. If you're restoring or maintaining a classic Yamaha, these are an essential, inexpensive part to keep in your toolkit. Stop that annoying fuel drip!