The 100318903 Bulkhead Flange Clamp is designed for NW25 size ISO-KF vacuum flanges and is made of aluminum. Bulkhead flange clamps are used to join an ISO-KF flange to a chamber or base plate. This two-part bolted clamp fits over the ISO-KF flange with a centering ring required for a vacuum seal. The bulkhead flange clamp kit includes the two-piece flange clamp, bolts, and washers. Series 31 ISO-KF vacuum components are designed for use at subatmospheric pressure and use standard interface dimensions defined by the International Standards Organization (ISO) allowing them to be interchangeable with other ISO-KF compliant components. Series 31 components can be used as modular building blocks to create vacuum piping systems. IS-KF flanges are "sexless" with a symmetrical seal so that so that components are rotatable. ISO-KF vacuum flanges are joined by inserting a centering ring between the two flange faces, and securing them with a flange encompassing clamp.