F connectors series are economically priced connectors specially designed for use with NTSC TV ANTENNA and other similar applications.  

F type joining devices use for 75 Ω cable assign system, especially CATV, broadcast television network.  

It can also be used for having impedance to mate the occasion required and can be used in not mating the occasion too.  It is joined, inserts helping jointly that its characteristic is whorl, the price is suitable .