"NSN USED TO PURCHASE A MINIMUM OF 1 CONTAINER TO A MAXIMUM OF 2 CONTAINERS;CERTIFICATION PWA 1317,GE B50TF40 CLASS B AND RR 9507/27;RB 90-95 HARDNESS;2500 PSI MINIMUM STRENGTH;EASILY MACHINED WITH ALL GRADES OF CUTTING TOOLS;DENSE CLEAN BRIGHT COATING RESISTANT TO OXIDATION AND CORROSIVE GASES AT TEMPS TO 1800 DEG (F)"