Champion Power Equipment 50-Amp RV Generator 30-ft / 1 3-Prong Outdoor Heavy Duty Locking Extension Cord in the Extension Cords department at Lowes.com
Superior Electric RVA1536 50' 50Amp RV Extension Cord Plug with Handle
RV Power Cord 15 ft 50 amp With Rain Proof Twist Lock Connector, 15 Foot / 50Amp | eBay