The D.T. Systems R.A.P.T. 1400 Training E-Collar provides a quick and easy way to train your retriever. Its Rapid Access button provides quick corrections and can be programmed to 16 different levels of stimulation, so youll be able to customize your dogs training. Patented, revolutionary curved transmitter design and function with 3 grip positions place on your knuckles, in your palm or in a pistol grip. This system can expand to a 2-dog or 3-dog system with the purchase of additional add-on collar (sold separately). The collar is waterproof, rechargeable and fits small to large dogs.