Dogtra has developed a "sound recognition and filtering microprocessor" that distinguishes a dogs' barking from its surrounding ambient noises. The model YS300, an intelligent no-bark collar, is fitted with this self-activating micro processing sound analysis technology, which only responds to the barking of your dog. The YS500 is a fully-waterproof no-bark collar designed with the same reliable electronics found in the popular Dogtra remote training collars. Long lasting rechargeable Ni-MH batteries, charger included.