The 100761220 Flange Bolt and Nut Set is designed for joining two size NW200 or NW250 ISO-BF bolted flanges. This set of 304 stainless steel hardware includes (12) M10 threaded 50 mm bolts with 1.50 mm pitch, (12) M10 nuts, and (24) M10 washers which is what is required to join NW200 or NW250 vacuum flanges. Series 76 ISO-BF flanges and seals are designed to be tightened to metal to metal contact. It is important that the bolts not be over tightened or warping of the flanges could result. The torque rating for flange bolts is 7 to 10 pounds per foot.