Check the listing for details. SportDOG Add a Dog Receiver Extra Collar SDT54-16292 SD-425X-425-825X SDR-AF. Color: Black, Condition: Used. Listed at 64.91 USD. SportDog Replacement / Add-A-Dog Collar SDT54-16292 removed from new SD-825X system with copy of retail store receipt for proof of purchase and warranty purposes ! Please Note: Includes only the Brand new receiver (as pictured), so you will need a compatible charger. Compatible charger available link below :https://ebay.to/393287E Part Numbers: SDT54-16292, SDR-AF SYSTEM COMPATIBILITYFieldTrainer 425X (SD-425X), 425XS (SD-425XS), 425 (SD-425), 425S (SD-425S)SportHunter 825X (SD-825X), 1225X (SD-1225X), 1825 (SD-1825X), 825 (SD-825), 1225 (SD-1225), 1825 (SD-1825)SportTrainer 575 (SD-575E), 875 (SD-875E), 1275 (SD-1275E)WetlandHunter 425X (SD-425XCAMO), 1825 (SD-1825XCAMO), 425 (SD-425CAMO), 1825 (SD-1825CAMO)ProHunter 2525 (SD-2525)HoundHunter 3225 (SD-3225)UplandHunter 1875 (SD-1875)