.187 Jack Screws Keystone Electronics .187 Jack Screws are 4.8mm diameter (.187') screws designed for D-subminiature connectors used in computer cables and other electronic equipment. The product portfolio includes standard jack screws, a sems version with a captivated helical spring-lock washer that simplifies use, a slotted option for installation with a screwdriver, and a screw with a nylon patch that firmly holds the jack in vibration applications. Keystone Electronics .187 Jack Screws feature a 3/16 hex head and 4-40 thread and are offered in stainless steel or with zinc chromate plating in yellow or clear.