This is an energy-saving password lock that does not need any power supply at all. It is suitable for indoor and outdoor doors. The 2-4-bit password is very safe and easy to install. It is a suitable choice. If you use the initial password, please keep the initial password card（Each lock has a different password）. If you forget the password, you will not be able to open it from the outside and need a professional to unlock it. Specification: Colour: Silver Panel size: 107*42*25mm Panel Material: Aluminum Alloy Lock material: steel + zinc Applicable door thickness: 30-60 mm Lock tongue center distance: 60 mm Note: Both left and right doors are applicable, password numbers can not be repeated (like 8888) Package Included: 1 x Password lock 1 x Instructions (English) Note: Due to the different display and different light, the picture may not reflect the actual color of the item. Thanks for your understanding. Due to different producing batches, product details might be a little different. If you minding the difference, please buy it carefully.