The TA170 is an 18 GHz 50 Ω SMA (m-f) connector adaptor often referred to as a "connector saver".
This is because this type of adaptor is often fitted to an expensive piece of test equipment such as sampling oscilloscopes or component that requires a lot of connect/disconnect cycles.
If one of the connectors becomes damaged, it is far cheaper to throw away and replace the connector saver than to repair the expensive equipment that it is protecting.
