Garmin Pro 550 Dog Training System MULTI-DOG - Ability to train multiple dogs at once, with purchase of additional dog devices (PRO 550 = up to 3 dogs) RANGE / FREQUENCY 1 mile range with 27MHz radio frequency for PRO 550 BARKLIMITER Built-in BarkLimiter with Advanced Bark Correction Technology STIMULATION LEVELS and 21 levels of continuous and momentary stimulation for PRO 550; easily control the stimulation levels by using the top-mounted selection dial on the handheld VIBRATION PRO 550 only - adds vibration control option for training UPLAND BEEPER PRO 550 only - handheld has the ability to remotely operate the accessory Upland Beeper (sold separately) Includes - PRO 550 handheld, dog device, 3/4 black collar strap, AC adapter, split adapter cable, charging clip, contact point set w/ wrench, manual Classic, rugged design Train with stimulation and tone Built-in Bark Limiter Tough, water-resistant, long-lasting Tri-Tronics technology