This is a PL259 - TNC Aerial adaptor for hand held transceivers such as the Maycom AH27, Eurosonic KH-104, and the Realistic / Radioshack variants.

Also for WLAN applications.

This will enable the removal of the 'rubber duck' type antenna fitted to these handhelds and an external aerial to be fitted via a PL259 plug. The world's your oyster then - you can connect a mobile aerial fitted to a magmount on your car or even a full size homebase aerial !