Dumb waiter lifts are small lifts which usually open at “serving height” (approximately hip-height) for easy hand loading between 2-6 floors.
You’ve probably seen one in a restaurant or hotel, the most common places for them.
Dumb waiter lifts are usually seen around commercial kitchens as it allows the kitchen staff and chefs, and the restaurant serving staff, to pass items between floors without dangerous or time consuming journeys up and down stairs with breakable plates and the like.
Hotels also use dumb waiter lifts for transporting items like laundry or cleaning products between floors.
Larger private homes sometimes install a dumb waiter lift too, providing convenience and a method for transporting items. House staff can also use the lift in the same way a hotel or restaurant would as well.