Carabiner for a rope, a strap and/or a further carabiner, comprising: - a main body having a 'C' configuration, between a lower free end and an upper free end which identify an inlet opening for the insertion of a cord or rope, the upper free end being provided with at least one protrusion, - a closing element, wedged in said lower free end and configured so as to elastically pass from a closing configuration, in which said lower free end and said upper free end connect together, so as to prevent the passage of the rope through the inlet opening, to an opening configuration in which it deviates at least partially from the protrusion of the upper free end so as to allow the passage of the rope through the inlet opening, - wherein the closing element comprises a first branch and a second branch, having a first lower interlocking end and a second lower interlocking end, respectively, interlocked to the lower free end of the main body, and a second upper closing end which, in a closing configuration, makes a shape coupling with said protrusion, - wherein said first branch and second branch are arranged in an X-shaped configuration, crossing at an intersecting point, on opposite sides with respect to a centreline plane (M-M) of the carabiner connecting the upper free end and the lower free end, - wherein the upper closing ends of said branches (36,40) are connected to each other by means of an arc-shaped portion which at least partially embraces said protrusion, in a closing configuration, on the side of the main body, said arc-shaped portion also making a front undercut which opposes the rotation of the closing element on the side opposite the main body. - a main body having a 'C' configuration, between a lower free end and an upper free end which identify an inlet opening for the insertion of a cord or rope, the upper free end being provided with at least one protrusion, - a closing element, wedged in said lower free end and configured so as to elastically pass from a closing configuration, in which said lower free end and said upper free end connect together, so as to prevent the passage of the rope through the inlet opening, to an opening configuration in which it deviates at least partially from the protrusion of the upper free end so as to allow the passage of the rope through the inlet opening, - wherein the closing element comprises a first branch and a second branch, having a first lower interlocking end and a second lower interlocking end, respectively, interlocked to the lower free end of the main body, and a second upper closing end which, in a closing configuration, makes a shape coupling with said protrusion, - wherein said first branch and second branch are arranged in an X-shaped configuration, crossing at an intersecting point, on opposite sides with respect to a centreline plane (M-M) of the carabiner connecting the upper free end and the lower free end, - wherein the upper closing ends of said branches (36,40) are connected to each other by means of an arc-shaped portion which at least partially embraces said protrusion, in a closing configuration, on the side of the main body, said arc-shaped portion also making a front undercut which opposes the rotation of the closing element on the side opposite the main body.