Secure your doors and windows with the KlikAanKlikUit Contact sensor Door / Window ALMST-2000. With a magnetic contact sensor on your window or door, you know when it is forced. The sensors do not give a signal themselves. That is why they must always be used in combination with the ClickOnClickOff siren. The contact sensor works on batteries. Thanks to the battery indicator, you know exactly when to replace it. With a range of up to 70 meters indoors you have enough space to provide most windows and doors with sensors (depending on the size of your house).