Dogtra Dummy Collar (Small) Works with the following models: 175NCP, 180NCP, 200NCP Series, 210NCP Series, 280NCP Series, 300 Series, 7000 Series, EF-3000, EF-3000 Gold. Features: For dogs 10 - 25 lbs Looks and feels like a real collar 3/4" x 29"