This European Standard specifies the characteristics of protective covers for plugs in the family of circular, electrical connectors, with triple start threaded coupling. It applies to models in Table 2.For plugs, see EN 3645-008, EN 3645-011 and EN 3645-012. These connectors are derived from and interchangeable with models W, F, K and Z in specification MIL-DTL-38999/32.