This Agilent Varian OEM TriScroll 300 KF-25 intake spool fitting is used to make vacuum connection between the roughing line and the intake to the outboard scroll of the scroll pump module. The intake spool fitting has a machined o-ring groove at its bottom face where a Viton o-ring is compressed to form a vacuum tight seal against the outboard scroll. The intake spool fitting is made of aluminum.