Italian to English Tech/Engineering Furniture / Household Appliances kitchen accessories

as in "piletta a chiusura assistita" where piletta means the drain in a kitchen sink and chiusura assistita means ?

Very techno kitchens these, so could mean a number of things and no there is no context/picture/drawing to help, I'm afraid. Maybe just those plugs that you move up and down with a lever or twisty bit? Help!
Thanks for any pointers. Sue.