The PetSafe PBC00-10677 Comfort Fit Bark Control Collarfeatures Perfect Bark™ Technology. Unlike other bark collars where correction is triggered by vibration, the Comfort Fit Bark Collar requires a combination of sound and vibration to trigger the electronic correction. This prevents unneccessary correction. The PetSafe Comfort Fit Bark Collar will stop dog barking the minute it’s placed on your dog. The bark collars automatically adjust the level of Static Correction (6 levels) to your dog’s temperament. The new QuickFit buckle allows you to put the collar on or remove it in a matter of seconds. It also provides a perfect fit every time for added comfort. The Comfort Fit Bark Collar senses the vibrations in your dog's throat that happen only during barking. This prevents false corrections from other dogs barking. This will stop dog barking. This PetSafe Comfort Fit Bark Control Collar is recommended for any dog over 8 lbs. It's durable yet light weight collar is 100% waterproof and adjustable to fit any dog. It has 6 levels of self-adjustable corrections adjusting to the bark intensity of your dog. PetSafe PBC00-10677 Comfort Fit Bark Control Collar features: Six levels of self-adjusting correction Patented Perfect Bark Technology that uses both Sound and Vibration for Correction Low battery indicator light QuickFit™ buckle provides a quick release and a perfect fit every time Automatic safety shut-off if your dog continues to bark more than 15 times in 50 seconds Durable, 100% Waterproof Receiver Collar Flexible Collar provides a Comfortable Fit Sophisticated microprocessor technology provides a warning beep with the first bark Not too strong for small or timid dogs...yet strong enough for large or stubborn dogs Adjustable collar with QuickFit Buckle for neck sizes 8” - 28” Initial Battery Included (PetSafe RFA-67) Complete Operating Guide Receiver collar specs: 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"