These Schumacher Racing Products o-rings are a factory replacement Speed Pack for nitro and fuel system sealing applications across compatible Schumacher platforms. Sized at 3.3mm outer diameter with a 2.4mm inner diameter, they are sold in a pack of 6. Keeping a supply on hand is recommended practice for any nitro RC build where o-rings are subject to wear from fuel and heat exposure. Features: Pack of 6 o-rings 3.3mm OD / 2.4mm ID sizing Suited for nitro fuel system sealing Schumacher Speed Pack factory replacement 7/7/26 cs