The General Estienne launched in 1921 a study of the future battle tank and called on the manufacturers who have already participated in the production of tanks during the conflict that has just ended. Five prototypes were presented in 1924: SRA, FCM 21, Famh, Delaunay-Belleville and SRB or Renault-Schneider Type B

None of these prototypes will be adopted. However, the experience acquired makes it possible to define the specifications of the future tank B and these devices are at the origin of the Dual tank, a concept which will be followed until the beginning of the Second World War.