This Green male plug is an easy and quick solution to putting a polarized plug on SPT-2 zipcord. Make your own extension cords with our zipcord using these plugs or use them to create custom length C7 or C9 based light stringers. Also known in the industry as vampire plugs, this green male plug simply slips over the end of a cut cable. Slide on the cover, you've connected the plug to the wire and you're good to go.