Fecha de publicación: -- Fuente: WIPO "tomato" There is described a lid group (15) configured to be associated to a collar (8) of an opening device (3) for a package (1) filled with a pourable product The lid group (18) comprises a lid (9) movable between a closed position and an open position in which the lid (9) is configured to, respectively, close and open a pouring outlet (11) of the collar (8) and a coupling ring (14) comprising a main portion (23) configured to surround the collar (8) and extending along a direction parallel to a longitudinal axis (F) of the coupling ring (14). The main portion (23) has a non-circular shape.