New Old Stock Listing is for all 10 Multi-Dog Systems. Each system works with 2 dogs Great for someone that works with multiple dogs or pet store since this listing is for 10 of these This lot of 10 Multi Dog Double Training System Rechargeable Waterproof Bark DT-101 is perfect for dog owners who want to train their dogs effectively. The system is designed for dogs of all sizes and types, and it includes a rechargeable battery and waterproof design to ensure that it lasts for a long time. With this training system, you can easily train your dog to stop barking and improve their overall behavior. It is manufactured by Flittor Dog Training, a trusted brand in the pet training industry, and it is specifically designed for dogs that are difficult to train. The DT-101 model is highly effective and has been proven to work in various studies. So, if you want to train your dog efficiently, this lot of 10 Multi Dog Double Training System Rechargeable Waterproof Bark DT-101 is definitely worth considering.