Device including a tubular element (1), with a flexible printed circuit (3) of conducting tracks (32) on which are a number of LED diodes (31) and contact ports (33) for supply thereof; a flexible cover (2), formed by a coextruded profile with a diffuser back (21), configured in a flexible material and a base (22) made of a material of greater rigidity; said base includes a longitudinal aperture (23) and a set (25) of male and female configurations connectable by pressure for opening and closing the inner recess (24) for reception of the printed circuit (3); and an external connector (4), comprising two sets of electrically conducting connection pins (41a, 41b), or a holder (42c) with contacts (40) for the electric contact of the ports (33) and tracks (32), to terminals (45) for connection to the external supply.