Looks like some sort of fan - probably home made as I've not seen anything like that before.
On my list of things to do over winter is sort a locking, cerbo gx relay controlled (so remote & temperature controllable) fan fitted to a vent in a sliding window.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.