This 2 in 1 Alarm Security Bar is specially made for sliding glass doors and hinged entry doors. As soon as someone pushes the door, the alarm will sound like a powerful siren or barking dog to warn you that someone is trying to enter. An effective way to frighten away intruders. Easy no tool installation. Constructed of heavy gauge steel and uses one 9-volt battery (not included). Features include: For Added Security & Protection Powerful Siren or Barking Dog Sounds! Secures Your Home from Intruders! Alarm Sounds When Door Knob is Touched Heavy Gauge Steel Construction No Installation Required Protects Any Room Any Time: Home, Dorm, Office, Hotel & More! Heavy gauge steel constuction prevents door from openingExtends from 29 to 43 inches to fit any doorFits inside sliding doors up to 72 inches wideIncludes retail packaging