Storz hose couplings are comprised of interlocking hooks and flanges, and are sometimes referred to as sexless couplings because rather than having male and female ends that connect by screw threads, Storz connectors have identical ends that can be joined to any other end of the same size.
The Storz Permanent Hydrant Adapter is a blind cap with a metal sealing surface that threads onto the male nozzle and is secured permanently to the hydrant. Storz adapters are hard anodyzed aluminum, with the cap connected to the adapter with a 0.125" vinyl coated aircraft cable. The female adapter contains a flat rubber gasket to secure the Storz connecter to the male hydrant nozzle. The high-torque cap requires a Storz spanner wrench for removal.