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 (22, 30) 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 (22, 30) 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).