A: 12v 4ah ( Radioshack, Fry's Electronics )

Q: What kind of battery do I need to replace the battery in the transmitter for the contact?

A: There are 2 types of transmitters for contacts.

Contact	Contact	Motion
3v lithium cr 1620	6v lithium battery	6v lithium battery

Q: What kind of battery do I need to replace the battery in the motion detectors?

A: Motion detectors are going to take a 6v battery. Most take 2 although there are some that take more. Carefully open your motion detectors cover to verify the battery you will need.

Q: How will I know if my batteries are low?

A: The keypad will display the zone number as well as battery.