Specification: Product model: 38D Panel material: zinc alloy Password length: 2 to 4 digits Applicable door thickness: 10 to 60mm Applicable type: indoor, outdoor door Features: water, no battery Center distance of the lock tongue: standard 60mm Lock Size: about 107 * 43 * 20mm / 4.2 * 1.7 * 0.8in Package list: 1 * Mechanical lock set 1 * English manual 2 * Installation package Note: The passwords are not in order, the numbers cannot be repeated, refer to the manual. Change the Password: 1. Remove the 4 red screws from the rear panel of the outer door keyboard. 2. Open the back panel and be careful not to tamper with many small parts inside. 3. See 3 red ciphers, 6 blue regulars and 1 C. 4. Press the C button to move the internal lock piece, but do not move the C piece. 6. Pay attention to the different characteristics of the red and blue locking tabs and insert them into the slots. 7. After placing it, cover the back panel after correcting it. After tightening, check it repeatedly. Edit the password button according to your own, and you can unlock it smoothly and confirm the success. 8. Please pay attention to that there are spare locks in the accessories, you can change the number of passwords to 2 to 4.