This thing is worthless. It was featured on a website by Publishers Clearing house. I was told it would be about $4.99 with shipping and the bill was over $17.oo. No return information on the product just an invoice for payment. DO NOT BUY THIS PRODUCT. YOU CAN NOT TELL IF IT WORKS. THERE IS NO INDICATOR LIGHT. My dog just barks anyway . It goes back somewhere and no payment will be given read full review »