I had a rack failure awhile back and lost some animals. After that I went out looking for something to alert me if this ever happened again. I use this one from http://www.lacrossetechnology.com/alerts. The unit works great and I've never had a problem with it. The major benefit to a unit like this is the expansion capability which means every rack and my incubator are all attached sending me updates if things go beyond the range. Plus I can just look it up on my phone if I ever feel the need to check it wherever I might be.