A coupling that can be easily and repeatedly rotationally adjusted after assembly and/or installation. The coupling can comprise a male part insertable into a female part to a first position whereat the male part is rotationally locked with respect to the female part. Upon further insertion of the male part into the female part to a second position, the male part is rotationally unlocked from the female part and the male part then can be rotated relative to the female part. Once rotational adjustment is complete, the male part can be returned to the locked position to rotationally lock the coupling.