I have been going thru my vacuum system trying to get everything up to par, and have a funky rubber elbow that needs to be replaced (existing is cracked and leaking). My local parts store can't determine what it is, and I don't know what it for. I have a photo of the part attached below:
The arrow is pointing to the fitting I need. Any ideas what this is or where I could get one?

The arrow is pointing to the fitting I need. Any ideas what this is or where I could get one?