This is a complete replacement for old Thetford waste dump valves. It has a flat top for direct mount to a proprietary Thetford 4-hole flange. On the bottom outlet side, it has a 1-3/8" long 3" spigot (3-1/2" OD). Made of ABS, the spigot is designed to be solvent welded into an ABS hub with a 3-1/2" ID. The blade is plastic. Comes with handle. Top seal and four mounting screws are included.
This is version 08708 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.