You leave the pies in their tins they were baked in; you don’t attempt to turn them out before putting them on this rack.
They can be made out of steel or wrought iron. Each one usually holds at least two pies, if not three, and is designed to sit on a counter. Some unusual models are designed to maximize counter space by actually hanging on the wall, with the rings of the rack folding down for storage.
Each tier of the rack is a ring, designed so that the pie tin sits down into it, with the ring nestling under the rim of the pie tin to hold in. The pie plates usually have to be a certain minimum size so that they don’t fall through, usually at least 8 to 8 1/2 inches (20 to 21 cm) wide.
Pie Racks tend to be somewhat ornate compared to the simple racks designed to cool cakes and cookies on so that they can also be used for “presentation” at buffets and picnics. Pies can be served right out of their tins sitting in the rack.
You can also get slatted ones made of wood, designed to hold just pie. You can also just use regular wire racks.
If you have big enough plates, you can sit plates on top the rings to use the rack instead to hold sandwiches, desserts, etc.
Almost all require hand washing if anything gets spilled on them.