The SD-825X model uses the smallest collar of the family while still providing up to ½ mile range for up to 3 dogs. Check it out at Okie Dog Supply.
SportDOG Brand FieldSentinel 825 Electronic Dog-Training System
SportDOG® SportHunter® 825X Remote Trainer Dog Collar at Menards®
SportDOG SportHunter 825X Free Shipping - Front Range Gun Dog
Wetlandhunter® 425x - Store
SportDOG Contain + Train Add-A-Dog Collar - PTS16039
1 MILE RANGE: One mile range e-collar that can support training up to 6 dogs with the same remote with purchase of additional collars (SDR-AXW). For
SportDOG Brand WetlandHunter 1825X Camouflage Remote Trainer - Rechargeable Dog Training Collar with Shock, Vibrate, and Tone - 1 Mile Range
SportDOG Brand FieldTrainer 425X/SportHunter 825
Expand your system to multiple dogs or use as a replacement collar/receiver for the SD-425, SD-425X, SD-825, SD-825X, SD-575E, SD-875E and more
SportDOG SDR-AXF Collar Add-A-Dog Receiver for SD-425X SD-575 SD-825X SD-875
SportTrainer® 825X – SportDOG® Spain