The Ducellier D703 is a reliable capacitor designed for classic Citroën and Peugeot models such as the DS, ID, HY, 11CV, 15CV, and the Peugeot 504 and J5. This capacitor plays a crucial role in a vehicle's ignition system, helping to build up sufficient electrical tension for the spark plugs. With its solid construction, the Ducellier D703 is durable and resistant to conditions under the hood, making it a favorite among classic car enthusiasts who value authenticity and reliability in their vehicles.