A housing includes a display unit indicating a complete plugging of a counter-plug into the housing and a first stop. The display unit is movable along a longitudinal axis between an initial position and an assembly position. The display unit includes a locking element, a guide element, and a supporting element. The locking element has a resilient bridge with a first end fixed to the guide element. The first stop prevents the display unit from moving in the initial position by abutment with a free end of the bridge. The free end is bent in a bending plane in a direction of the guide element when moving toward the first stop. The supporting element supports the bridge at the guide element when the bridge deforms in the direction of the guide element and prevents a deformation of the bridge away from the abutment on the first stop.