A valve comprising: an internally hollow main body (2) having at least one inlet opening (3) and at least one outlet opening (4) in fluid communication with each other; a closure member (6) rotatably in engagement inside said main body (2) so as to rotate between an open position at which it allows passage of fluid from said inlet opening (3) to said outlet opening (4) and a closed position at which it inhibits passage of fluid between the inlet opening (3) and the outlet opening (4); a substantially annular support (15) disposed at least at one of said openings (3, 4) and defining a through cavity (16) for enabling passage of fluid in the open position of said closure member (6), the support (15) having a first sealing element (18) in contact with an inner surface of said main body (2) and a second sealing element (19) in contact with an outer surface (8b) of said closure member (6); the sealing element (18) being in mechanical and/or chemical clinging relationship with the support (15).