Generac Connector CS6364 T/L 50A 125/250V - TremTech Electrical Systems
Legrand Pass & Seymour Turnlok 50 Amp 125/250-Volt California Standard Connector CS6364 - The Home Depot
AC WORKS NEMA 14-50P to CS6364 Connector 50-Amp 4-wire Single To Single Orange Basic Compact Adapter in the Adapters & Splitters department at Lowes.com