Simon XT Wireless Door & Window Sensors

Crystal sensors use Lithium 3.6V batteries, which last 8-10 years. They do have built in tamper switches, so if someone tries to tamper with your contact, your alarm panel will let you know.

Micro sensors use Lithium 3.0V batteries, which last 5-8 years. They are much smaller in size than the average sensor. They do not have built in tamper switches.