Almost all doors and windows are monitored by a Visonic MCT-302. This is a Door/Window sensor with 2 inputs. The first one is controlled by the magnet, the other one, the auxilliary contact, can be used for other purposes like for instance the mailbox. Visoinc sensors all operate at 868 MHz and can be received by a RFXCOM receiver.
Visonic MCT-302
And i use 2 KAKU AWST-606 sensors, for the front and back gate.
KlikAanKlikuit AWST-606