Material & Silent:Our hidden door hinges are made of high-quality zinc and alloy materials,ensuring they are sturdy and enduring,corrosion resistant and has a long service life. The built-in copper structrue spacer ensures that the door moves smoothly and quietly, enhancing the function of hidden doors or secret passages. Durable and great value for money.Hidden Design:Our hidden door hinges can be used to create invisible doors, folding doors, and other feature walls. The completely hidden design ensures that there are no visible hinges, make your door look stylish and sophisticated, perfect for any commercial or intensively used door, including wooden doors, flush doors, metal doors, fireproof doors, noise isolation doors, security doors, etc.3-Way Adjustability:Our invisible door hinges can be adjusted in 3 ways as needed: vertical 2.5mm, horizontal 2.5mm, and depth 1.0mm allows fine-tuning without disassembling the door, which is very convenientsuitable for DIY enthusiasts and professionals.AFTER-SALES SERVICE:If you encounter any difficulties, such as receiving a defective item, contact us immediately. We provide 24-hour customer service and offer a 30-day money-back guarantee. Your satisfaction is our top priority.Dimensions:Our concealed door hinges measures 62.51 inches and is suitable for door thicknesses >35 mm1 3/8 in. The door width < 900 mm. Two hinges support up to 88 pounds and a 180-degree opening angle,providing reliable performance for your hidden door or secret passage.