Parveen Industries Pvt. Ltd. Offers Blue Subs Red Nut Hammer Unions. The Blue Subs Red Nut Hammer Unions falls in the category of Treating Irons, Unions, Swivels and Circulating Heads. Parveen Industries Pvt. Ltd. Is an ISO 9001: 2000 certified company. The Blue Subs Red Nut Hammer Unions are designed for high pressure systems like choke and kill lines, cementing , acidizing, testing and truck mounted system. This union has a lip type seal made of nitrile rubber and subs made of alloy steel, suitable for 10,000 PSI.