DMSB hold joint responsibility for determining the sporting regulations of the Euro Series. The organisation and promotion of the championship is handled by ITR, which performs the same role for the DTM touring car championship. Venues The championship consists of ten events, each comprising two races, held at a variety of European circuits. Approximately 50–60% of these events occur at circuits in Germany, while the other events are held in various countries, including Great Britain, France, the Netherlands, Italy, Belgium and Spain. Most rounds are shared with the Deutsche Tourenwagen Masters. Notable venues have included Pau and Le Mans in France; Brands Hatch in Britain; Circuit de Catalunya in Spain; Estoril in Portugal; Adria in Italy; and Spa-Francorchamps in Belgium. From 2004 onwards, the Masters of Formula 3, held at Zandvoort in the Netherlands, was included as a round of the championship. In 2005, the series visited Monaco as a Grand Prix support event, which was the first Formula Three event at Monaco since 1997. This famous motor-racing venue has long-standing associations with Formula Three. Technical and sporting regulations The FFSA and DMSB created the new championship around the FIA-sanctioned F3 formula of multiple chassis builders and production-based 4-cylinder 2-litre engines with control supplies of tyres and fuel. As in most F3 championships, the Italian company Dallara is the dominant chassis supplier. It was originally planned to restrict entry to two-car teams, but this requirement was later relaxed. In most Formula Three championships, multiple and single-car entries are common. Some Formula Three championships, such as the British Formula Three Championship, use a two-tier system to provide an opportunity for low-budget teams and drivers to compete with out-dated chassis specifications. In an effort to minimise costs, Formula Three chassis regulations permit major updates only periodically, with annual updates restricted to minor improvements. When the Euro Series was launched, restrictions were effectively placed on the teams' choice of chassis specification by opting not to create a lower-tier championship class, and all entrants used the two most recent available specifications. There is a rookie classification system with a Rookie of the Year title for drivers who have not previously competed in this championship. The Drivers' Trophy was introduced in 2006 to provide a classification system and class title for drivers using chassis of between two and four years old. Eligibility for this "B class" was restricted to drivers who were not more than