... steel seat** Unique sealing ring, with saw-tooth sides, embedded directly into disc, bolt-free connection, easy on-line ... service life.** Unique taper pin, US patent design pin, bolt free & clearance free connection, eccentric pin maintains strength of shaft, ... for long serviceGood exchangeability** Excellent sealing effect** complies with BS 6755, part1, 1986. Valve sizeDN50-DN600Pressure rating ...