Holland Electronics
This F-81 Female "F" to Female "F" (double-ended Female) connector allows for connection thru a 1/8 inch thick wall plate (typical), passing Cable TV and TV Antenna Signals to above 1 GHz. Not Recommended for Satellite with Power Feed. You can also use this to connect (splice) two "F" fitted coaxial cable ends together. You can select the washer and nut needed to fit a wall Plate from the accessory box above. This F-81 is 11.6 / 8.1 mm. (long side/short side) with a total length of 21.2 mm. You can also use this to connect (splice) two "F" fitted coaxial cable ends together. Use on Cable TV Antenna Frequency connections.
An adapter (or adaptor) is a device used to match the physical or electrical characteristics of two different Connectors so that a connection may be made between them and the Equipment You desire to Cross-Connect. Most Connections for Video and RF (Radio Frequency) Equipment is 75 Ohm in Characteristic Impedance. Radio and Microwave Frequency Connections Passing High Power Require 50 Ohms. A Majority of the Adapters offered Here are 75 Ohm. However, with the High Quality Dialectric Found Surrounding the Interior of the Mating Connection, Low Power Usage, and Transition Impedance Matching of Like Characteristic Impedances, Resulting Mis-match of 50 Ohm use woiuld be so Low as to be Considered Negligible.