describe LARGE AND SAFE STORAGE: The capacity of the large combination key box is large enough (internal size is about 4.5*3.7*2 inches) to hold house, office or other large car keys; if necessary, you can also store some small things, such as Credit cards, ID cards, etc. Two unlocking modes: This combination key safe has a 4-digit code and emergency key; it allows to define up to 10000 combinations. You can set your own password and change it regularly for added security, making it difficult to crack. In case you forget your password, the emergency key will be more useful! EASY TO INSTALL: This outdoor key safe comes with 4 screws and 4 nylon expansion wall anchors to ensure the combination key box can be installed to any sturdy surface. No fuss or extra work to drill a box into the wall at a higher cost. Sturdy Construction: Our wall key boxes are made of sturdy aluminum alloy that is resistant to water, corrosion and weathering. Ideal for external installation. Wide Application: This large outdoor key box can be widely used in home, garden, office, etc. It will be a great helper for any occasion. It allows you to keep and protect your car keys while surfing, rather than risking hiding them under sand/rocks etc. Have you ever hid your keys under a doormat or in a flower pot when you're not home, but worried it was safe?