This was purchased to protect my 2nd phone (1st phone already protected by a phone guard purchased a couple of years ago) as the kids were running up the bills. Great little device and works a treat. Able to programme numbers that all can call either by full code and number, area code allowing calls to any with that code, or say, 1st digit allowing all call that start with that digit. Facility also dial a unique code as a pre-fix to the number which allows that call through. Payback after 1st months bill, saving there after.