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.
I have used MCM for many years and would give high recommendation for getting the job done right.