4 AWG to 1 AWG, Single Ball-Point, Welding Cable Connector - 1UYF4|1UYF4 - Grainger
WeldingCity 2-pk Tweco-Lenco Style Twist-Lock Insulated Male Connector for Welding Cable 3/0-4/0 (70-95mm) in Miller Lincoln ESAB Welders (Pack of 2 Male Connectors) - Amazon.com