These Schumacher Racing Products o-rings measure 9.0mm inner diameter by 1.0mm cross-section and are sold in a pack of 10. They are factory replacement seals used in gearbox and drivetrain assemblies across a wide range of compatible Schumacher and other RC platforms. Having spares on hand is practical since o-rings are wear items that should be replaced during routine drivetrain maintenance. Features: 9.0mm x 1.0mm cross-section dimensions Pack of 10 o-rings Drivetrain and gearbox application Schumacher Racing Products factory replacement part 7/7/26 cs