I have all vet records, as well as chip certificates on pdf files and loaded on my android phone and my tablet. If ever needed, I can email a shot record or any other documention to the vet while I'm standing at the front desk did that once.
Also I put one of these (similar mine are red) on each dog collars with a small piece of paper noting the campground and campsite I am located in. It's the size of an ignition key and made of aluminum, very light. Not sure if it would work for something like a chihuahua; might drag on the ground.