Hi Gary, "I was wondering what experiences other owners have had with battery cut off switches." I also have the cut off switch with the big red plastic key, I don't know what brand it is. It was already installed in my car when I bought it last year. Mine however is installed in a strange but handy place. The previous owner drilled a hole in the wooden backboard right next to the battery compartment cover. The key comes through the carpet right next to where the carpet flips up to reveal the battery cover. If I take out the key it just leaves a small black round key hole that is covered by the carpet (I can even let the key in there and drape the carpet over the key). The strange part is, that the connection is not inside the battery compartment but on the other side of the right hand wall so I can not see how it is connected without removing the wooden backbord. It works fine though and it is as good as invisible. Mads de Bruin Netherlands VIN#06881