School alert: Sonitrol.

www.sonitrol.com/safeschools, Hardware, $300-$500

This security system consists of fixed panic buttons that are placed in common areas around school and wireless emergency buttons carried by school administrators via lanyard or keychain that can be activated anywhere in the building. When pressed, the buttons activate audio sensors and/or video cameras. Monitoring personnel can hear or see events occurring in real-time. Other features include an integrated door control system that allows schools to limit and control access to their buildings, as well as theft-prone areas such as computer rooms, science laboratories and administrative offices.