Castline

castline_cables Castline Silver 35mm TRS to 1/4 TS Summing Cable with Resistors Mogami 2582 wire
https://castlineusa.com/index.php/instrument-cables/trs-to-ts

We are introducing new Stereo to Mono summing cables with resistors.
This cable is needed to connect MP3 players, portable CD players, cell phones, and other devices which have 1/8" (3.5 mm) TRS output to amplifier, mixer, PA systems and other devices wich have 1/4" (6.35mm) TS input.

Also, this cable prevents sound distortions and equipment damage.

http://castlineusa.com/index.php/trs-to-ts