Abstract: The invention relates to a connecting piece for a tubing including a first unit and a second unit, the first unit including a first connecting element for a tubing element and a second connecting part for the second unit, the second connecting element including a tubular female part for engagement with the second unit and first sealing elements, and the second unit including a tubular male part with a collar and second sealing elements for cooperating with the first sealing elements, the first and second units further including separator elements. The invention is characterized in that the sealing elements include a locking device; and that the separator elements and the locking device are arranged at a distance in relation to each other.