5100 Series Low Spill Connect Under Pressure Quick Disconnect, Male Half, -12 Coupling, 3/4-14 Female Pipe

You can connect it while the line is pressurized, up to 500 psi. That's one of the main reasons folks reach for this series in working hydraulic setups where shutting things down to make a connection isn't practical. Just keep in mind that ceiling is 500 psi for the connect-under-pressure feature, so if your system runs hotter than that at the moment of connection, you'd want to manage pressure accordingly before hooking up.

The plug has a 3/4-14 female pipe thread (NPTF) on the pipe end, and it’s a -12 coupling size in the 5100 Series.

You can connect it under pressure, up to 500 psi. That's one of the main reasons this coupling gets used on dump trucks and refuse vehicles where bleeding the system every time just isn't practical. The tubular valve design keeps fluid loss to a minimum during that process, so you're not making a mess or losing much product when you make the connection hot.

It's designed for on-highway hydraulic wet lines, as well as fluid and bulk liquid transfer.