SportDOG's YardTrainer SD-105 was designed for dogs 8 lbs and up. The trainer has a range of 100 yards (the length of a football field!) Perfect for training in the back yard, dog park or anywhere else where your dog might have the freedom to roam. With features such as a tone only button on the side, a continuous stimulation button a twice as strong continuous stimulation the YardTrainer SD-105 has all the features a companion pet will need.