CAMCO Yellow L14-30P to TT-30C DogBone Adapter | UL Listed | 125V 3750W | Outdoor Use | 12-Inch Long in the Power Adapters department at Lowes.com
Amazon.com: Camco PowerGrip Camper/RV Generator Adapter | Features a 4-Prong L14-30 Male End and a Standard 50-Amp Female End | Rated for 125/250 Volts & 7500 Watts (55422) : Tools & Home Improvement
Camco Power Grip 30A Male to 15A Female RV Plug Adapter - Henery Hardware