This eccentric (or offset) pipe reducer is available in two sizes. Each transitions from 3" pipe to a smaller pipe. The eccentric design is really good in black or gray systems to keep the waste flowing.
Made of ABS and solvent welded to ABS pipe.
The 3" side is a spigot (same diameter as a 3" pipe) and is designed to slip into a 3" hub. The small end is a hub and is designed to be solvent welded around the end of a 1-1/2" or 2" pipe.