[NEW 2019] Humane Bark collar-Dog bark Collar-Anti Barking Collar Small Dogs Medium Large Dogs-Rechargeable Waterproof Anti bark Collar-No bark Collars Sound Warning Vibration Electric Stimulation Utility Grade 1/2" standard nominal pipe size, slip x slip Very High Quality. Look for CPR UPC. Don't accept immitations Pack of 10 High Quality Silicone Washer. See image, not to scale.