Thank you! It’s a 18mm to tube connector from chemistry sets, I found the part on either Amazon or wish.

Edit: here’s the link to the part on Amazon

Glass Elbow Adapter Frosted for Extreme-q&v Tower, 2-Pack https://www.amazon.com/dp/B07WC9LLGH/ref=cm_sw_r_cp_api_glt_fabc_XEK2D8J8H4XTQ3J3VR26