RS Machine/Electric Plug Socket Screws These Machine Screws from RS are produced in mild steel with a nickel-plated finish. Also known as Electric Plug Socket Screws, these high-quality machine screws come in longer lengths making them easier to install. The bright nickel-plated finish makes these screws ideal for use with chrome accessories. Relevant to damp environments. Steel nickel plated finish suits most electrical switch and socket finishes.