British Standard Pipe (BSP) fittings are used to connect pipe together by way of a variety of male and female joiners. Male (BSPT) fittings are tapered and include nipples, which can be in the form of a hex nipple, barrel nipple or toe (threaded one end) nipple. Female fittings, sockets, couplings or joiners are parallel and are a most common joiner for two male parts. Combinations of both male and female fittings are available in adaptors and elbows. Other useful BSP fittings may include barrel unions, elbows, tees, crossed, bushes, caps, plugs and hosebarbs. While the male and female parts seal by the pressure of the treads, a thread tape or sealing paste is recommended.