What is this pipe part ??

This pipe part intrigued me and I'm hoping someone can shed some light on what it's purpose is please. Love the salt glaze and I would guess that it was made by Crum.

It has a large hole in the middle of the 'cap' and a rather small hole in the side.

Ev It might be worth your while getting in touch with Bryan Heron. He is a plumber, philanthropist and Crown Lynn enthusiast. He lives above Limeburners Bay and has interest tales of its recent history. If your piece is drainage or plumbing related he may be able to identify it.

Ev, ask John Buchanan, he is a pipe enthusiast... I just created a new group on his behalf... will go and join you up! You need to be in more FB groups, 😉😉😉lmao