SportDOG FieldTrainer 425XS Electronic Collar - The SportDOG Brand FieldTrainer 425XS is their 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. For dogs 8 pounds or larger with neck sizes 5in - 22in Charge in 2 hours, last 50-70 hours per charge