Residential window bars are commonly the basic 8 by 8 pattern or the 8 by 16 inch pattern. These bars are Open Style for situations where an exit is still needed. These are great for bedrooms, shops 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.
This is the cost to make a window bar open and lock.