2nd Generation Mechanical Combination Lock: This mechanical keyless entry door lock features a full mechanical structure that's resistant to tampering and requires no charging or batteries. With simple installation and operation, it provides excellent anti-theft protection. The 2nd generation also makes password changes easier, and the adjustable left/right handles add more flexibility Universal Compatibility for Different Doors: This mechanical keyless door lock comes with multiple screw sizes and a square shaft, fitting doors with thicknesses from 1.4 to 2.5 in (35-65 mm). It's compatible with a variety of doors, including courtyard gates, garden gates, garages, storage rooms, wrought iron, aluminum, and fence gates Durable Zinc Alloy Material: The latch bolt is made from zinc alloy; this keyless mechanical combination door lock has a corrosion-resistant electroplated coating, ensuring water and rust resistance