I seem to recall there used to be one but I've had trouble locating it online. (killzoneblog.com)
If you are having trouble locating it on your pet, have your veterinarian show you where to check at your next visit. (petpeoplesplace.com)
They sit under a slit in the seat upholstery and parents may have trouble locating them when installing a forward - facing convertible [JG4]. (cars.com)