L'occhio dietro la parete / Eyes Behind the balls (1977)

Director: Giuliano Petrelli
Writers: Giuliano Petrelli
Stars: John Phillip Law, Fernando Rey, Olga Bisera

Ivano (Fernando Rey) is a rich, wheelchair-bound writer in need of some inspiration just as much as his much-younger, sexually-neglected wife Olga (Olga Bisera) is in need of some male companionship. The couple have rented an apartment on their property to self-destructive loner Arturo (John Phillip Law); an eccentric man they hand-picked because of his good looks and the aura of mystery surrounding him. Using some strange electronic periscope device, the two are able to spy on their new tenant and get their vicarious jollies that way, but both want to go even further than mere spying…

Thanks to original uploader