Is there a special j pipe for a shower drain? Or do you just use 90 to make the j pipe and if so what are the specs so no sewer gas leaks...
Whoa! Not so fast there Markee. That "j pipe" is called a trap. And before I even answer I want to know a little more about this project. New installation or are you replacing a existing shower? What size is the drain pipe the trap would connect to? What kind of a shower? Tile? Plastic or fiberglass shower enclosurer? How far along are you on this? What "specs" are you asking for?
I'll wait on your answer, Tom