Equipment constructed for studying reactions induced by the external beam of the Birmingham cyclotron is described. An arrangement of proportional counters with absorbing foils, the whole rotatable in azimuth, is used for measuring angular and range distributions for the protons or other emergent charged particles. Both rotation and foil-changing are remotely controlled, completely avoiding health hazards for the operators during the experiments. The present paper describes principally the mechanical system; the counting systems are varied somewhat for different experiments, and are therefore described only in outline.