parkworld 1.5 ft. 10/4 4-Wire Generator 20 Amp 125/250-Volt 4-Prong L14-20 Plug to 50 Amp 14-50R Female-Outlet (L14-20P to 14-50R) 60417A - The Home Depot
parkworld 3 ft. 125/250-Volt 20 Amp Generator 4-Prong L14-20 Splitter Cord NEMA L14-20P to (2) L14-20R Receptacle Y Adapter Cord 885866 - The Home Depot
L14-20P Power Cord Plug Adapters | Twist Lock L14-20 Plug to 15A, 20A, 30A Locking Connectors
Conntek PL1420L1430 NEMA L14-20P to L14-30R Pigtail Adapter
NEMA L14-20 20A Receptale 125/250V Twist Lock Outlet Generator 46508 USA | eBay
Conntek 20591 & 20592 NEMA L14-20 Generator Extension Cords
AC WORKS 1.5ft NEMA L14-20P to NEMA L14-30R 20-Amp 4-wire Single To Single Black Basic Flexible Adapter in the Adapters & Splitters department at Lowes.com
Parkworld 691920A Generator to Welding Adapter cord NEMA L14-20 Plug 4-Prong 20A Locking Male to Welding NEMA 6-50 Receptacle 50A Female - - Amazon.com