The 100311303 Blank Weld Stub Flange is made with 304 stainless steel and is intended to be for turned, bored, or tapped to fit. This blank weld stub features a size NW25 ISO-KF vacuum flange and has a 0.75 inch overall length. 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.