There are generally two types of tags and labels in use in the United States. RF 8.2MHz and AM 58KHz. Some tag types are only available in one of the frequencies such as the "Supertag  II" which is exclusively an AM 58KHz tag but the problem is other tags such as "pencil" tags and "tamper resistant" tags look the same in both frequencies. The best way to tell what frequency your system and tags are is AM  58KHz tags are predominantly used with a "Sensormatic" branded or styled antenna system at your front door. If you see a Sensormatic label on anything then you are quite assured your tags are AM 58KHz. If you don't see Sensormatic then there is a good chance your tags and system are RF 8.2MHz. If you have any Remaining doubt at all give us a call or send us a picture of your system and tags and we will let you know before you buy!