a tubular male coupling member 1 and the a tubular female coupling member 10 can or cannot be disassembled depending of the position and angle of each tab in the moment of the insertion of the projections in the preferred embodiments of the invention the joining is permanent in a second embodiment of the invention illustrated in fig2 the snap coupling system between coupling members of a quadrangular cross section to be assembled in a u201c u201d fashion of the present invention this comprises a tubular male coupling member 20 of a quadrangular cross section having a first side wall 21 a and a second side wall 21 b an upper wall 22 a and a lower wall 22 b a first and a second slots 23 a 23 b parallel to each other both made transversally at an intermediate portion of the side walls 21 a and 21 b extending from the edge of the lower wall 22 b to the upper wall 22 a a first retention tab 24 a and a second retention tab 24 b not illustrated both practiced between the slots 23 a and 23 b in each side wall 21 a and 21 b beginning from the lower wall 22 b to the upper wall 22 a presenting a retention edge 25 a and 25 b not illustrated respectively a tubular female coupling member 30 of a quadrangular cross section to.