The By-pass lock is a 5" long keyed lock that sets 10" above your original lock. Being the key is 5" long that puts this lock behind all of the steel so it will be protected in case of a fire, vandalism or if your combination or digital lock should ever malfunction you can use this 5" long key to by-pass your lock and get in. Do not keep your key in your house its best to keep it a different location.