An instrument is configured for use with a receiving part defining a recess for receiving a rod to connect the rod to a bone anchoring element. The instrument includes a tube having a first end and a second end, and defining a coaxial internal channel that opens towards the first and second ends, and at least one protruding portion monolithically formed with the tube that is engageable with the recess of the receiving part to prevent rotational movement of the tube relative to the receiving part. The first end of the tube forms a closed ring. The at least one protruding portion has a first region that extends radially outwardly from an outer surface of the tube at the first end and a second region that extends axially away from the first end in a direction opposite the second end.