Window bars come in two types: fixed and unlockable. The unlockable models are easy to remove, using a key, in case of an emergency so you don’t loose your fire exit.
Bandit bars have the visual deterrence of fixed window bars but are easily removed in emergencies or to clean the window. They are wired to a burglar alarm system so if removed, they will trigger an alarm.
Patio bars stop the patio door from being opened more than a pre-determined amount. Models also available for windows.
Security screens protect window openings even while the window is open. An alarm will be triggered if the screen is cut or removed.