The RocLok Hide a Key is the only rock hide a key on the market to incorporate a 3 digit combination lock for added security. The combination lock has 1,000 possible code options and is easily set when in the unlocked position. Rated for the RV industry, our combination lock is built to withstand the elements and if cared for properly will weather without fear of corrosion. If you happen to live in an environment that is known for easily corroding metal outdoors such as near the ocean, we suggest applying a silicone based oil from time to time to ensure the lock is always in good working order.