This is a complete replacement for old Thetford waste dump valves.   It has a flat top for direct mount to your holding tank.  It has an "O"-ring connection on the bottom outlet side to fit in a 3" hub.  Blade is plastic.  Comes with handle.  Seal and four mounting screws are included.

This is version 08706 of Thetford valve 01447. Every Thetford valve ever made says 01447 on it, so you can't rely on the number molded into the plastic to guide you in selecting the correct version.