The 100761332 Flange Bolt Set is designed for joining a size NW320 ISO-BF bolted flange to a size NW320 tapped flange. This set of 304 stainless steel hardware includes (12) M12 threaded 60 mm bolts with 1.75 mm pitch and (12) M12 washers which is what is required to join NW320 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.