For connecting RCA Outputs to XLR inputs.
 
RCA outputs are found on DJ controllers, Mixers, CD players, and other souce equipment.
 
XLR inputs are usually found on Powered speakers, Amplifiers, Equalizers, Processors, etc.
 
Note: Many Mixing consoles have their XLR inputs labelled as "Mic" or Microphone input. Connecting a line-level source (such as your DJ controller) to these mic-in's will give you distorted sound. It is recommended in this case to use the 1/4" Stereo channel inputs.