Double female to female barrel connector to connect male UHF/PL259 cable to another male UHF/PL259 connector - very handy for connecting extra length RG-8/213/LMR400, etc. cable to another
OCF antennas are very convenient as they will allow multiple bands of operation with a simple wire antenna which is fed off center with a 4:1 OCF Current balun with built in feed line choke,