EZ-Release Nylon Digital Dog ID Collar
These collars are for dogs only, and are not meant for cats.
Here are a few different methods for measuring your dog's neck:
Method 1) Measure your dog's neck with a sewing tape while keeping two fingers between his skin and the tape.
Method 2) Wrap a string around your dogs neck with two fingers between his skin and the string. Mark the string and then measure the length of it.
Method 3) Remove your dog's current collar and stretch it out flat. Then measure from the center of the buckle to the current sizing hole being used.