These are the things I found on the internet which doesn't tell me too much.
http://www.crystaltag.com/pages/faq1.htm http://www.classypets.com/Merchant5/..._Code=PTSCHIPS
I guess the Crystal Tag is at a 134 khz frequency whereas most US Tags are 128/125khz. I have my baby's neutering scheduled for next week and I wanted to get him microchipped during this time. His vet only uses Crystal Tags and I don't want to get him something that is useless in which case I will need to take him to another vet since I want to take care of both procedures at the same time. I take him to a great vet but oh what to do!