The SportDOG Brand YardTrainer 105S is designed specifically for tougher or stubborn dogs and is the perfect choice for introductory training and obedience. The SD-105S features a higher range of stimulation than the SD-105. The waterproof, compact Collar Receiver features a range of 100 yards, and the easy-to-use, water-resistant Remote Transmitter has 8 levels of stimulation and a tone-only button.