The SportDOG Brand FieldTrainer 425XS is our smallest and lightest e-collar built for in-the-field training or hunting with close working dogs. This S' model was built for high-drive, more stubborn dogs by offering a higher static stimulation range than the SD-425X. Consistency and perfect timing are critical to developing your sporting dog, so the remote is quickly and easily operated without having to look at it - which lets you focus on your dog and not your equipment. with only a slight movement of the dial and the push of a button, you will be able to deliver a tone, vibration, or one of the 21 levels of static stimulation. Use these stimulation types to communicate with up to 3 dogs (with purchase of Add-A-Dog collars) out to 500 yards with any of the 425 models.