While surfing, looking for a Med ID tag for my human pet, I found these programmed USB flash drives for pets. I'll order a couple for our dogs even though their computer expertise is limited to getting hair in the computer tower. In my not-so-humble opinion, these should only be used
in addition to more-conventional dog (or cat) ID tags. But these hold a lot more info, room for multiple phone numbers and contacts, home address, second-home address, RV description, medications, home area vet, etc. The two tags together should help bring Fido (a.k.a. Lucy & Simba) home.
Hope this is helpful to a few of our many pet lovers here.
The human med ID tag at the website is a little larger, and, yes, my human pet is going to get one of those too!
http://www.healthtechservices.com/PTHome.html