A nut (10), comprising: a female thread (34) for threading a bolt (14) thereinto; a head (52) surrounding the female thread (34), for holding the female thread (34), for allowing rotating the bolt (14) in relation to the female thread (34); and a self-tapping thread (36), for threading the nut (10) through an object (18), the self-tapping thread (36) characterized in not providing linear pacing in relation to the object (18) upon rotation therebetween upon completing the threading therebetween, wherein the self-tapping thread (36) may comprise the female thread (34) for threading the bolt (14) therethrough, thereby allowing connecting the nut (10) to the object (18) and then moving the bolt (14) in relation to the object (18), thereby allowing fixing the object (18) to a building structure (20) at an adjustable distance (40).