A male and female coupling are used to join a hose and the thread is what connects them together to form a tight seal. A female coupling, also known as cap and tail, has threads on the inside and a male coupling has threads on the outside. Hose couplings can also be known as hose connectors or hose fittings and some of the main hose couplings are IBC couplings, Bauer couplings and Camlock couplings. Measure across the thread with a ruler or vernier for accurate BSP Fittings.