Gramin’s PRO 550 delivers advanced training sessions for serious professionals, and comes packed with features right out of the box. The user can choose between 21 levels of continuous and momentary stimulation, tone, and vibration for the greatest effectiveness and choice over the entire range. The PRO 550 can also sync up to 3 different collars (sold separately), allowing the user to train 3 dogs at the same time and has a one mile range. Other features include a remote activated LED beacon on the collar to help locate your dog in low light conditions, as well as BarkLimiter – a feature that uses Autorise technology which adjusts correction to the optimum level to stop unwanted barking. In addition, the PRO 550 transmitter and collar are waterproof and are built to stand up to the bumps and blows of training and hunting. Features of the Garmin PRO 550:1-mile range Can sync up to 3 different collars21 levels of continuous and momentary stimulation, tone, and vibrationIntegrated BarkLimiter LED beacon Waterproof Garmin PRO 550 System Handheld and Dog Device Bundle 010-01202-00