21 levels of continuous and momentary stimulation, built-in BarkLimiter, one-mile rangea |it's the ultimate in behavioral conditioning, the very best for your hunting dog-in-training! The PRO 550 with proven Tri-TronicsA(R) technology allows advanced training for the serious professional with easy access to 21 levels of momentary and continuous stimulation, as well as the ability to quickly switch between 3 dogs (with the purchase of additional collars). PRO 550 features vibration and tone settings, remotely operated beacon lights on the dog device to help locate your dog in low light, and a built-in BarkLimiter, activated on the dog device, to help keep the peace at home. Read on for the whole story... Train with Stimulation and Tone Choose from 21 levels of continuous and momentary stimulation, tone, and vibration for up to 3 dogs at a time. You can also remotely operate the LED beacon lights, built-in to the dog device, to help locate your dog in low light conditions. Classic, Rugged Design The PRO 550 uses the tried and true tube-shaped design that trainers have come to love, but is easy to operate (and master) one-handed. You can keep your eyes on your dog at all times, even while switching between stimulation levels and dogs. The stimulation level / vibrate selection dial is at the top of the transmitter, allowing intuitive operation. Tone, beacon lights and beeper are controlled using the switch,and buttons on the face of the handheld unit. And the control buttons comfortably line up in the hand for fingertip control. A 2 1/2" fixed transmitter antenna eliminates the threat of a lost or broken antenna while delivering up to one mile range. Built-in BarkLimiter PRO 550 features a built-in BarkLimiter, activated by the Collar itself. BarkLimiter features Autorise technology, which automatically adjusts correction to the optimum level needed to stop unwanted barking.