Residential window bars are commonly the basic 8 by 8 pattern or the 8 by 16 inch pattern. These bars are permanently fixed, so for fire exit, see Window Bars Open Style. These are great for shop and garages, and lower windows that are easy to pop open, or easy for thieves to pry into, let alone smash and grab things just inside. This only takes a robber seconds, and alarms will not deter them from quick theft attacks. Steel physical products will make them go to another place and leave yours alone.