Best Seller | SportDOG Brand FieldTrainer 425/SportHunter 825 Add-A-Dog Collar The original Collar Receiver for FieldTrainer425 and SportHunter825. Add another dog to your current SportDOG Brandelectronic training collar system or replace a Collar Receiver with the SDR-AF Add-A-DogReceiver Collar. Comes with a convenient docking... more | | $159.95 FREE shipping go to store |