SportDOG SD-1825CAMO Transmitter Compatible with: SD-425, SD-425S, SD-425CAMO, SD-825, SD-1825, SD-1825CAMO, SD-1875 Contents: Remote Trainer, Antenna, Belt Clip and Lanyard 16 levels continuous stimulation, 8 levels Momentary Stimulation, Tone and Vibration options Up to 1 mile range Expandable up to 6 dogs