This is a female threaded tap connector with a 3/4" BSP thread.  It incorporates a fine gauze particle filter which is easily removed for cleaning.

Screws directly onto any tap with a Male 3/4" BSP thread (common on most outdoor garden taps)

This item also has a male Snap On connection which enables the connection of a standard 1/2" (ID) garden hose.  A female snap On hose connector is also included to complete the connection to the hose.  

It can also be used to fill watering cans and other containers with filtered water without attaching a hose pipe.