SportDOG WetlandHunter A-Series 500 yard Remote Trainer &ndash; SD-425CAMO Up to 500 yards range. 7 instantly selectable static stimulation levels with medium/high ranges. Available option to train with vibration and tone. Expandable up to 3 dogs. Charges in 2 hours, lasts on average 50-70 hours per charge depending on usage of the remote trainer. DryTek waterproof and submersible to 25 feet. Recommended for dogs 8 pounds or larger with neck sizes 5" - 22".