The PT 10 dog device works with the PRO 70, PRO 550 and the Sport PRO handhelds, allowing you to add more dog device collars to your pack. Train up to 6 dogs on 1 PRO 70 handheld, 3 dogs on 1 PRO 550 handheld or 3 dogs on 1 Sport PRO handheld (additional dog devices required) with a range of 1 mile, plus remote-operated LED beacon lights for low light conditions and built in BarkLimiter, activated on the dog device, for a quieter kennel.