interior dimension within the collars 90 and 100 thus the inside configuration and dimensions of the collar should generally be configured to conform to the pipe or rail outside configurations and dimensions in order to allow them to seat therein in order to allow for a smooth transition area between the pipe 110 and the collars 90 and 100 two o rings 120 and 122 are utilized the o rings 120 and 122 are such wherein they allow for a smooth and elastomeric transition as far as the step or ledge goes between the outside dimensions of the collars 90 and 100 and the pipes 110 thus they provide somewhat of a protected surface any form of ring collar plastic clip flange or spline can be utilized in place of the o rings 120 and 122 the thought being that they should provide for less tearing and destructiveness of any object bumping into the interface of the collars 90 and 100 and the pipe 110 also the collars 90 and 100 can have a chamfered edge rather than having the covering they can taper and fair downwardly circumferentially or have a fillet toward the pipe 110 or have any other conformation which allows for a smooth transition between the two respective portions of the collars and pipe in order to hold the collars together a pin such as a cotter pin 124 is shown the pin has a protuberance 126 which allows it to be implaced within an opening 128 of the.