"It is made of silica gel (same stuff found in those little packets of desiccant that are sometimes found in various
dry food packages, inside new leather goods, etc). "
We used to use a product like this when attempting to get urine samples from cats. Some would use it, some would turn up their noses at it. And the best part was that veterinarians are generally speaking a thrifty group of people so we always had to wash it and re-use it. (Wonder where all the bacteria in the urine came from?)
Critter
