Proving & fixing iSi Marked Non-return valves flanged end class PN-1.0 as per iS:5312/2004 in pipe lines including jointing & cost of Nut Bolt , rubber insertion etc. complete. Note: if Non-return valves class PN-1.6 is used instead of class PN-1.0 , than 5% will be paid extra. Class PN-1.0 as per iSi with gun metal flap 100mm i/d Non-return valve