Descriptions:1.Material: Made of zinc alloy, with smooth finish, corrosion resistant,  resistant to wear or tear,  sturdy and durable, easy-to-grasp, ensure long service life.2.Advantages: Use on your bedrooms, bathrooms and other privacy needs. It can be locked inside with a turn button and unlocked outside with provided release tool. It be sure to add a touch of sophistication to your home.3.Installation: Tighten the the assembly screws with a screwdriver and complete installation. Keep the door knob hardware steady and securely attached. It fits both right and left handled doors.4.Note: Please carefully confirm the size to meet your needs before purchase. If our product has problem, please feel free to contact us anytime.Specifications:Color: Matte BlackMaterial: Zinc alloyRound lock overall length: 162mm(6.38inch)Applicable door thickness: 1-3/8" (35mm) to 1-3/4" (40mm)Package Contents: 1 round lock, 4 screws (thread length/total length/thread diameter: 12.5/14.5/3.5mm), 3 keys and an instruction manual.