This is exactly what I wanted for myself to provide an extra sense of security. As a single female renter, I always felt a little concerned about the maintenance guys, office staff, previous tenants, and any number of other service providers that had keys to easily enter my apartment. While I doubt this little gem will stop anyone who is bound and determined to gain access regardless of the consequences, I do believe it will deter those that attempt entry accidentally or who want to go unnoticed...