So the difference is purely in how the two connect to your sewer pipe, which will also tell you which one you need; one will slide into the pipe (the spigot) while the other will slide onto the pipe (the hub):
- Slide Into Pipe: Valterra Waste Valve for RV Black Water Tank - 3" Spigot to 3" Lug # T50A
- Slide Onto Pipe: Valterra Bladex Waste Valve for RV Black Water Tank - 3" Hub to 3" Lug # T50
To secure the valves to your pipe you would just need the Valterra ABS Solvent Cement # A05-0303. view full answer...