24-650 - RCA Plug to 2 RCA Jacks
RCA "Y" Cable
Commonly used in a variety of audio applications including combining left and right line level signals to a mono input, or splitting a single line level signal to feed two amplifier inputs.
24-770 - RCA Jack to 2 RCA Plugs
Divides a RCA signal input into two outputs.
30-2570 - Outdoor Balun Transformer 300 Ohm to 75 Ohm
Outdoor Balun Matching Transformer
This matching transformer is used to connect your 75ohm coaxial cable to the common 300 twin style connection on many outdoor antennas. The CM 94444 is an industry standard balun which offers excellent matching and low loss.
I have dealt with MCM Electronics a number of times and have been more than satisfied.