This PetSafe collar is designed for small dogs and is compatible with the RFA-476 Trainer System. The collar has been thoroughly tested and is in great working order. It is perfect for training your furry friend and helping them learn basic obedience commands. The collar is made by PetSafe, a trusted brand in the world of pet supplies, and is specifically designed for use on dogs. This collar is a great addition to any pet owner's training toolkit.