Clasp comprising a cover connected to a first bracelet strand and to a second bracelet strand, a connecting means being inserted between the second bracelet strand and the cover of the clasp, the connecting means comprising an end link sliding between a first position in which it is engaged in the cover of the clasp, and a second position in which it is outside the cover of the clasp, the end link comprising a push-button which causes a toothed element to change from a first position, in which the toothed element is in mesh with a rack toothing, to a second position, in which the toothed element is released, the end link being provided with an arresting means preventing the removal of the end link from the cover of the clasp, the arresting means comprising at least one lug, which projects into a groove arranged in the bottom of the cover and which defines two end stop members.