Bellows (1) connecting adjacent carriages (3), in particular carriages of a material handling sorter (2) along a predetermined path (P), being robust and reliable, comprises opposite heads (4a, 4b) each being associated with a carriage (3) and a pleated structure (5) with a preset number of substantially M-shaped elements (6) being provided with a plurality of vertices (7), as well as a bearing structure (8) formed by a base structure (8) and by a frame (8") slidingly abutting on the base structure (8% such base structure (8') and such frame (8") being rigid and cooperating with each other, being placed between adjacent carriages inside the bellows (1).