I have two units. Both are the standard version. One is a 1000 and one is a 2000. The 1000 is still working on the batteries I installed about a year ago. The 2000 went through 2 sets of batteries within the first 8 months. Needless to say, I don't rely on the 2000 model for home defense, I only use it for securing firearms out of access from children, and I quit replacing the batteries. I just use the key on it.