Abstract: Fittings of this invention comprise a body having a substantially hollow transport passage extending between a body first end and a body second end. The fitting body ends are adapted to accommodate attachment with respective fluid handling devices. The fitting has a hexagonal outside surface portion for grasping and rotating the fitting. An interlocking attachment member is disposed along an outside surface of the fitting body and is adapted to form an interlocking attachment with a complementary member of a fluid handling device when the fitting is connected thereto. The interlocking attachment member comprises a plurality of ratchet teeth that are configured to register with a complementary fluid handling device member. The fitting body first end includes a tongue that is configured to provide an interference fit within a groove in a fluid handling device opening to provide a leak-tight seal between the fitting the fluid handling device.