Six levels of self-adjusting correction, automatically adjusts to your dog's temperament starting at the lowest level Patented Perfect Bark technology for the most reliable bark detection Low battery indicator QuickFit?buckle provides a quick release and a perfect fit every time (patent pending) Durable, waterproof Receiver Collar Flexible collar provides a comfortable fit Lifetime Limited Warranty Height: 1.5" Width: 2.5" Depth: 1.25" Weight: 4.0 oz. Uses a PetSafe Battery: RFA-67 Waterproof Adjustable collar for neck sizes 8"-28" 6 levels of correction Progressive correction feature increases correction to next strongest level if dog continues to bark Safety time out will shut off the correction for 3 minutes if the dog barks more than 15 times in 30 seconds Uses vibration sensor to sense for barking Not recommended to use for more than 8 hours at a time Dog should be at least 8 lbs.