Abstract: A coupling for a nipple is disclosed. The coupling comprises a main body (100); and an opening (110), for a fluid, in the main body (100), the opening (110) being cylindrical. The coupling comprises further a holder (130) arranged in the opening (110) holding a plurality of locking elements (140) for locking the nipple to the coupling, the holder (130) and the plurality of locking elements (140) being separate; and a retaining element (150) retaining the holder (130) in the opening (110), the retaining element (150) engaging the plurality of locking elements (140). A method for assembling such a coupling is disclosed. The method comprises inserting the holder (130) with the locking means (140) into the main body (100); and retaining the holder (130) in the main body (100) with the retaining means (150).