Made of nickel-plated brass, the ECF504-AB USB A-B couplers come as an assembled kit that includes the UADKEY-AB keystone coupler and the ECF style mounting frame with two mounting screws. This is similar to the company’s ECF504-UABS adapters that use chrome-plated plastic. Naturally, the full-metal components target applications requiring greater stability and shielding. L-COM GLOBAL CONNECTIVITY, North Andover, MA. (800) 341-5266.