A pin header (or simply header) is a form of electrical connector. A male pin header consists of one or more rows of metal pins molded into a plastic base, often 2.54 mm (0.1 in) apart, though available in many spacings. Male pin headers are cost-effective due to their simplicity. The female counterparts are sometimes known as a female socket header, though there are numerous naming variations of male and female connectors. Historically, headers are sometimes called “Berg connectors”, but headers are manufactured by many companies.