A system for releaseably connecting a first device housing with a second device housing , comprising: at least three connection units , wherein each of the connection units comprises two parts, one comprising a headed bolt and one comprising a corresponding keyhole-shaped recess configured for receiving the headed bolt in such a manner that the headed bolt can be inserted into the recess in a first section and held in the recess in a second section , such that the headed bolt and the keyhole-shaped recess can be connected in a form fitting manner, wherein at least one of the connection units comprises a locking mechanism (9'; 9") configured for locking the bolt in the second section of the recess , wherein the locking mechanism; (9'; 9") comprises a movable locking element ( 21; 28) which is movable with respect to the headed bolt and configured to hold the headed bolt in the second section of the recess in a locking position, wherein the locking mechanism (9'; 9") comprises a locking catch wherein the locking catch is configured to catch the headed bolt in the second section of the recess , wherein the locking catch is arranged such that the headed bolt is locked automatically by the locking element when inserted into the keyhole-shaped recess and moved from the first section to the second section, wherein the locking element (21; 28) is configured as a slider transversely movable with respect to the bolt axis wherein the locking element (21; 28) is preloaded by a spring element such that the locking element (21; 28) is resiliently held in the locking position, and wherein the locking catch is attached to or integrally formed with the locking element (21; 28; 38). at least three connection units , wherein each of the connection units comprises two parts, one comprising a headed bolt and one comprising a corresponding keyhole-shaped recess configured for receiving the headed bolt in such a manner that the headed bolt can be inserted into the recess in a first section and held in the recess in a second section , such that the headed bolt and the keyhole-shaped recess can be connected in a form fitting manner, wherein at least one of the connection units comprises a locking mechanism (9'; 9") configured for locking the bolt in the second section of the recess , wherein the locking mechanism; (9'; 9") comprises a movable locking element ( 21; 28) which is movable with respect to the headed bolt and configured to hold the headed bolt in the second section of the recess in a locking position, wherein the locking mechanism (9'; 9") comprises a locking catch wherein the locking catch is configured to catch the headed bolt in the second section of the recess , wherein the locking catch is arranged such that the headed bolt is locked automatically by the locking element when inserted into the keyhole-shaped recess and moved from the first section to the second section, wherein the locking element (21; 28) is configured as a slider transversely movable with respect to the bolt axis wherein the locking element (21; 28) is preloaded by a spring element such that the locking element (21; 28) is resiliently held in the locking position, and wherein the locking catch is attached to or integrally formed with the locking element (21; 28; 38). <EOS>