The PetSafe Deluxe Bark Control Collar features 18 levels - 3 correction levels (low/medium/high modes each with 6 levels of correction) and is one of the smallest unit available at only 1.7 oz. The patented Perfect Bark Technology ensures that only a combination of both sound and vibration from your dog can activate the collar. A harmless static correction is then emitted to correct the behavior. Adjustable collar for neck sizes 6"-28". Waterproof unit comes complete with a PetSafe RFA-67 battery and operating and training guide. Shipping weight: 1 lb.