1-7/8-12 x 1-5/8-12 Male O-Ring Boss x Female O-Ring Boss Reducer/ExpanderThe 1 7 8 12 x 1 5 8 12 Male O Ring Boss x Female O Ring Boss Reducer Expander is a hydraulic fitting designed to connect components with different O Ring Boss (ORB) thread sizes. It allows for a transition between a larger male ORB thread and a smaller female ORB thread while maintaining a leak proof, high pressure hydraulic connection. The O ring sealing mechanism ensures a secure, vibration resistant joint, making it suitable for demanding fluid