STURDY AND DURABLE: Made of heavy-duty stainless steel with maximum corrosion resistance and durability, the hidden door center pivot hinges are made to provide reliable support for many years to come. PRACTICAL AND INVISIBLE: With unique roller ball design, these 360 degree rotating door pivot hinges provide an easy and efficient way to swing the door easily and quietly. Solid rotating door hinge with heavy-duty design and smooth bearings is almost invisible. EASY INSTALLATION: The top pivot comes with a retractable pin for quick and easy installation. The rotating door's hidden pivot hinge can be mounted on the upper level of the door and attached to a hole on the door's surface. WIDE APPLICATIONS: The hidden rotating door hinges work great for swing doors, murphy doors, and so much more. Excellent pivot set alternative when door weight load on traditional door frame hinges is an issue. BUY WITH CONFIDENCE: With compact design and solid construction, these rotating door pivot hinges are a nice accessory for your door hardware.