Usage Tips:1.Durable & - These residential door hinges are made out of premium iron material with mattefinish. They are constructed to be long-lasting and rust-proof, accompanied with stable and heavy duty performace2.Smooth Closing - Operated by plain bearing construction, these bifold door hinges features smooth.3.Applications - These interior door hinges can be mounted on door frames, wooden box, shed windows, shutters, vents for sheds, apartment, playhouses, animal shelters and other indoor and outdoor use.4.Fine workmanshiThickened zinc-based alloy blade, the blade is stamped in one piece by CNC lathe, super hardness, not easy to break, longer service life.5.Noise-Free - Damping oil is added to the pin, so our pin is non-removable but it is NOISE-Free, which means when you open and close this door, it doesn't creak.