External Size (HxWxD): 4.53 x 3.43 x 2.16in, Internal Size (HxWxD): 3.94 x 3.15 x 1.18in. The large storage capacity is enough to store keychains, bank cards, car keys, cash or other small objects. With this security key safe, don't have to worry about the keys you hid under the carpet being taken away. The anti-rust door key safe box is made of heavy-duty PVC, aluminum alloy and durable steel locking mechanism, which offers extra resistance for the box to resist against attack from hammering or drilling. And the weatherproof cover can protect the box from wind, rain, snow and dust. Key safe lock box uses a 12-digit multi combination to ensure robust protection, which offers up to tens of thousands different combinations, far more than 4 dial models, much more difficult for cracking. Easily to re-set your desired combination at any time. (Note: Take a photo/Write it down to save your code!) Only 4 simple steps to finish the installation: Drawing screw outline Drilling holes Nail into expanded plugs Install the box by screws.