The Internal Expanding Joint is an expanding type fitting for joining two tubes of the same size. The fitting is comprised of two parts which are inserted into the tube, the fitting then expands when tightened by means of a hex key. The 150 forms a smooth joint between two tubes.
This fitting can only be used for 3.25mm wall thickness tube (1”, 1 1/4” & 1 1/2” BS EN 10255, formerly BS 1387, medium weight) and must not be used as a load bearing joint, particularly for tensile loads. Type 149, which has superior load characteristics, may sometimes be used as an alternative.