I have been a fan of the Dogtra products for a long time, and the new Dogtra 3500 training system lives up to all of my expectations.  It has 127 power settings and operates in two modes, continuous or short pulse, and it has a special mild stimulation mode for super sensitive dogs.  This is one of the most flexible systems that I’ve ever come across, and it has been designed with the trainer and the dog in mind.  The anti-microbial collar casing and the surgical steel contact pins obviously benefit the dog.  The one-mile range, full waterproofing, rechargeable batteries, and battery life indicator are for the trainer.  The superior results and ease of use are for both the dog and the trainer.  The Dogtra 3500 training system is hard to beat!