The FieldTrainer® 425S takes the most advanced, industry-leading technology that SportDOG™ Brand has ever built into its e-collars and packaged it up in the most compact system ever offered. Designed specifically for tougher, more stubborn dogs, the 425S has a higher range of stimulation than the SD-425. The 425 series is ideal for training in the yard, field, or for hunting with close-working dogs. Switch instantly between stimulation, vibration, and tone to fit the correction or communication to your dog’s temperament and learning ability. This new 425S Model is an upgraded replacement for the FieldTrainer 400S.