Here are a couple of great alarm door sensor options for you: The Security Door Alarm at R259.99 is a highly rated contact sensor that will alert you whenever a door or window is opened. It has a low energy design so the batteries will last a long time. For extra peace of mind, you may want to consider the Door And Window Alarm Sensor at R199. This one allows you to monitor multiple doors and windows with just one receiver unit. Both of these sensors are affordable ways to add an extra level of security to your home. Let me know if you need any other details!