The Inferno is a powerful internal security sounder that effectively stops intruders in their tracks. Installation of the Inferno cheats the intruder of the time they may expect to enjoy between alarm activation and arrival of security or police. The unit is easily retrofitted and a number of units can be installed either in series or in parallel. The special sound waves produced by the Inferno make it exceptionally difficult to locate the source of the unique sound. Despite disorientation and the 'sound barrier shock effect', no long-term hearing problems would be inflicted upon the intruder.