Binoculars; Dog whistles; Earphones; Electric fences; Photographic cameras; Portable media players; Smartwatches; Telescopic sights; Walkie-talkies; Wearable activity trackers; Electronic collars to train animals; Global positioning system (GPS) consisting of computers, computer software, transmitters, receivers, and network interface devices; Lifesaving vests for use by dogs; Sighting telescopes for firearms