NEMA L6-30 (250VAC, 30A) twist lock electrical male plug - The Electric Brewery
AC WORKS 50-Amp 125/250-Volt NEMA 4-wire Grounding Heavy-duty Locking Plug, Black in the Plugs & Connectors department at Lowes.com
Leviton 120V 15A NEMA L5-15P Twist Lock Power Cord Plug [L5-15P] - $12.45 : Auber Instruments, Inc., Temperature control solutions for home and industry