A "standard-polarity" SMA male connector has a 0.9mm diameter center pin surrounded by barrel with inside threads, and the standard SMA female connector has a center sleeve surrounded by a barrel with outside threads. The centre pin is the same diameter as the centre of RG402 Coax so that connections can be made with no discontinuity, forming the pin from the coax itself. As with most other connectors, the gender assignment corresponds to the innermost electrical component. There are also "reverse-polarity" ("RP") SMA connectors in which the pin and sleeve are swapped so that the "male" RP-SMA has a center sleeve surrounded by an inside-threaded barrel, and the "female" RP-SMA has a center pin and an outside-threaded barrel. See below for a fuller description.