To reduce the height of the vehicle it has been made impossible for the crew members to retract their heads under the roof. To protect these vital parts two hemispherical armoured hoods ("calottes") have been fitted. These have vision slits but to improve the field of vision the front section of these hoods can like a visor be pivoted backwards over the back section. As otherwise a bar between the roof and the glacis would have hindered entrance, the forward hinging glacis hatches have an extension forming the roof section that fits around the front part of the hood; if the hood is retracted and the hatch opened, a larger entry space is thus available. An interesting feature of the vehicle is the internal communication system used. When the hoods are closed, the two crewmen, separated by the engine between them, cannot directly communicate; neither internal nor external radio communications are possible, as there are simply no radio sets fitted. A system of white, blue, green and red lights, that can be made to shine continuously or flicker, is used by the commander to direct the driver when buttoned up, based on a predetermined signal code: