This is a Defender 3kVA portable transformer, commonly used on construction sites to step down mains voltage to 110V for safer use with power tools. It has a tough GRP case and two 16A 110V outlets. It's designed for demanding construction tasks and can be used with tools like drills, grinders, and saws, as well as lighting and ventilation equipment. Resettable overload protection keeps tools safe and maximizes work time. The pictured model includes a 240V 13A plug and a 2m cable. It's designed to withstand harsh conditions and has features like recessed sockets and a durable nylon plastic casing. It is often used where mains voltage needs to be stepped down and isolated. The transformer is center-tapped to earth for added safety.