PetSafe No-Bark Collar, PBC-102 for $42.99

Curtail your dog's excessive barking with this harmless, easy-to-use nylon collar. Insert the included 6-volt battery into the lightweight receiver, and fasten the adjustable collar around the dog's neck. When the dog barks, the collar senses the vibrations in the pet's throat and emits a mild static shock and an audible warning beep. There are 6 progressive correction levels, so if the dog barks again within 30 seconds, the next shock will be stronger, though not too strong for small or timid dogs.