The Radio Systems PAC00-12914 Vibration Plus Trainer VT-3 Add-A-Dog is a utility-oriented training tool. It can be used as a replacement collar or to add another dog to two select training systems. This effective collar is easily programmable to convert your current Remote Trainer into an easy-to-use training system for two dogs. Featuring 15 levels of adjustable vibration corrections, this collar is waterproof, rechargeable and ranges up to half-a-mile. Highly functional, it's a great training accessory for a pet enthusiast or a pet trainer.