Innotek UltraSmart 2-Dog Remote Trainer, 300YDS Micro remote 2-dog trainer with pocket-sized handheld transmitter 300-yard range; 9 stimulation levels; tone-only training option Backlit LCD digital display; collars fit neck sizes 8 to 24 inches ReadyTest ensures correct collar fit and battery and system status Receiver measures 2-3/4 by 3/4 by 1-1/4 inches; transmitter measures 1-3/4 by 3/4 by 4-1/8 inches; limited lifetime warranty