E-collars work by delivering electronic stimulation to a dog. Misused, they can be inhumane. Used properly, e-collars are an invaluable means of long-distance communication, allowing you to correct a dog immediately in such a way that it leans after only a few stimulations. In most situations, you can train with very low levels of stimulation, or use a tone first, then stim, so that the dog quickly learns to obey upon hearing the tone. In other cases, merely using the “vibrate” setting is enough. At the other end of the spectrum, a collar set at a high level can break a dog from dangerous behaviors like running deer or approaching rattlesnakes with only a few, or even one, repetition.