Add a big dog to your Elite Big Dog Remote Trainer and Elite Little Dog Remote Trainer. From up to 1,000 yards away, you can communicate two pets from one trainer. The system works through a static correction administered by the handheld remote to your pet?s receiver collar. This collar, combined with the trainer (sold separately) includes 15 adjustable levels of static correction, + 2 boost options and tone-only options to find the correct level for your pet?s temperament. With quick, fun training sessions, your pet will soon learn his new desired behaviors, and he will be on his way to leash-free walks and playtime.