This is a single Fuel Line Sealing Ring from Febi Bilstein, part number 43540. It is designed for use with Mercedes Benz vehicles. The sealing ring has an outer diameter of 15 mm, an inner diameter of 10 mm, and a thickness of 2.5 mm. The product is made of NBR (nitrile butadiene rubber) and weighs 0.005 kg. Please ensure compatibility with your vehicle before purchase. This product is an authorized UK stockist item and is sold individually.