made major contributions to the few battles in which they took part. Models depicting vehicles from the World War I era and the following interwar years are not as numerous as their later world war counterparts, but this is beginning to change in recent years. As of the centenary of the start of World War I, more manufacturers have begun to release kits World War I and interwar subjects: Takom releasing a range of British tanks such as the Mark I and Whippet; Meng providing two variants of the FT-17 and the German A7V and Hobbyboss releasing an interwar Vickers Medium Mark II are all examples of this. Vehicles used between 1939 and 1945 fall into the World War II category. Even though this era spans the shortest number of years, it is by far the most popular for armor modelers due to the enormous range of vehicles used and the vast improvements in armor technology. During the early part of the war, most armored vehicles were smaller, less heavily armored, and lightly armed. Major tank engagements early on convinced governments on all sides of the need for more survivable and deadlier vehicles. This means that there is a large variety of different subjects which were designed to fulfil different roles under different doctrines. Any vehicle serving in a setting after 1945 is considered "modern." This encompasses a longer time span and very large number of armor designs from many countries. Models may also be categorized by place of service, for example, US or Soviet. They may also be categorized by function, for example, combat engineering vehicles, recovery vehicles, etc. In all cases, the national and unit markings on the replica determine the era and user nationality. For example, a model of a Sherman tank, a World War II design, would be considered a 'modern' model if the tank were shown in Israeli markings from the Six-Day War. The same vehicle in World War II US Army markings would be considered a World War II Allied subject. Models are generally built with historical accuracy in mind, and each model may represent many hours of research effort on the part of the modeler. Frequently, modelers display some of their research work alongside their model. There is generally some crossover of modelers between the eras, though some focus solely on a specific era, country of origin or operation, or even on a