The Theory of Operation and Installation Manual contains all of the information that you need to plan your installation and order the sensors that you will need:
SIS uses inexpensive wireless sensors that you can purchase from E-Bay or Amazon.com for under $10 each. The sensors are battery operated and the batteries should be good for a period of 6 months to several years. The main sensor type used in SIS is the wireless PIR motion sensor (shown above). SIS also uses magnetic separation sensors on exterior doors. Additional sensor types may be used within SIS. These include Water Level Sensors, Vibration Sensors and Keyfobs.
SIS compatible sensors operate in the 315 MHz and 433 MHz RF bands (SIS supports a mix of sensors operating on both frequencies). The modulation is On/Off Keying (OOK) and the sensors transmit codes compatible with the PT2262 and EV1527 protocols. The SIS release package also contains Arduino source code that transmits data that is compatible with SIS. You can use this software to create your own, SIS compatible sensors: