Abstract: The preferred embodiment of the invention disclosed herein includes a first sleeve member having a slightly enlarged diameter portion at one end thereof and a second sleeve member having one end telescopically received within the enlarged diameter portion such that said first and second sleeve members are movable between expanded and contracted positions. Also included is a third sleeve member fixed to the outer surface of the second sleeve member and extending axially about the enlarged diameter portion and a portion of the smaller diameter portion of the first sleeve member. The third sleeve member is radially spaced from the first sleeve member forming a pressure chamber which communicates with the interior of said sleeve members through ports formed in the enlarged diameter portion. Thus, fluid pressure acts in the pressure chamber to counteract separation forces in an associated pipeline.