WEN 25 ft. 30-Amp 10-Gauge STW Fan-Style 10/4 Generator Extension Cord (converts L14-30R to four 5-20R outlets) - Walmart.com
VEVOR 40 ft. Generator Extension Cord 110-Volt 30 Amp Generator Cord UL Listed Generator Power Cord with Twist Lock Connectors FDJYCX40FT30A0001V1 - The Home Depot
Champion Power Equipment Champion 25-Foot 30-Amp 125-Volt Flat Generator Extension Cord (L5-30P to Three 5-15R) - Yellow in the Generator Accessories department at Lowes.com