This patented Groco IBVF flanged adapter eliminates common (and dangerous) thread mismatches when in-line valves are screwed onto thru-hulls. They also accept standard thru-hulls into the base and standard in-line valves or other components on top.

In addition, they provide a safe and sturdy assembly when in-line valves are used as seacocks and prevent valve damage during engine or generator installation since the valve can be installed later. Finally, they make future valve replacement a simple job.