1. This set of semi-circular hinges is made of high-quality zinc alloy, which has high strength and durability. The opening angle is 90 degrees, recessed when opening, very suitable for office applications 2. The 90-degree opening and closing mechanism makes it very convenient to use, and can be used with cabinets or flap doors. This is a reliable product with more than 50,000 hours of opening and closing 3. Built-in hinge, adjustable accessories, used for wooden flaps and cover, supports up to 10 kg 4. Folding wooden round hinges, double cup hidden hinges, fully open and hinged cabinet doors, lifting hinges, flap hinges 5. Folding hinges are suitable for kitchens, bedrooms, wardrobes, cabinets and other small furniture90 Degree Double Cup Concealed Hinge Adjustable Concealed Cabinet Door Hinge with 90 Degree Page Rotation Axis 90 Degree Rotation Axis Adjustable Cabinet Door Concealed Hinges, Special Under-desk Hinges, Flat Hinges, Cabinets, Cabinet Hinges This set of semi-circular