Toro 0.351 Inch x 0.072 Inch OEM O-Ring. As with any Toro Genuine Part, Toro ring seals are designed for a specific application for retaining lubricants and fluids and protecting against debris and moisture that can damage tires, gears or motor components. The best way to assure that you are replacing worn-out seals properly is to order Genuine Toro Seals.