The 100314801 4-way Cross Fitting has NW16 size ISO-KF flanges on all 4 ports and is made with 304 stainless steel. Four-way cross fittings have one inlet and three outlets and can be used as cross branch lines ISO-KF vacuum systems. Series 31 ISO-KF vacuum components are designed for use at sub atmospheric 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.