3.5mm Female 1/8'' TRS Stereo jack to 2 Dual 1/4'' 6.35mm Mono TS Splitter ,6.35 to 3.5 mm Jack Adapter Cable (20CM) - Walmart.com
2pcs Audio Adapter Splitter 1/4 Y 6.35 Male to 2 Female 6.35 Mono Jack | eBay
hardware - Does professional quality stereo to mono conversion require a special adapter - Sound Design Stack Exchange
15cm STEREO 3.5mm Mini Jack to TWIN MONO RED WHITE Splitter Audio Cable Adapter | eBay
Amazon.com: VCE 2-Pack Gold Plated 3.5mm 1/8 inch Female Mono Jack to RCA Male Adapter : Electronics
Amazon.com: Devinal 3.5mm to Dual 1/4 Y Splitter Cable, 1/8" Female TRS to Dual 6.35mm TS Male Adapter, Female Mini Jack Stereo to 2 Quarter inch Mono Converter 1 feet : Electronics
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Amazon.com: Qaoquda 6.35mm 1/4 inch TRS Stereo Female to 2 Dual 1/4 Inch TS Mono Male Y Splitter Adiuo Cable 20cm/8inch (6.35F/2M) : Electronics
Chenghaoran 1/4" 2pole Mono 3 Pole Stereo Audio Jack Plug Adapter Male To Female 3.5mm / 6.35mm Dual Jack Headphone Microphone Y Splitter Converter - Connectors - AliExpress
microphone - Combine two mono mics into one stereo signal, such that each mic gets its own channel (left and right) - Sound Design Stack Exchange
3.5MM Stereo Plug to (2) RCA Mono Jacks Shielded Y Adapter
Amazon.com: TNP 3.5mm TRS to 2 Dual 1/4 Inch TS Stereo Audio Breakout Cable Adapter - 3.5mm 1/8" Female to 1/4" 6.35mm Mono TS Male Headphone Jack Plug Y Splitter Cable Combiner
Amazon.com: TNP 3.5mm TRS to 2 Dual 1/4 Inch TS Stereo Audio Breakout Cable Adapter - 3.5mm 1/8" Female to 1/4" 6.35mm Mono TS Male Headphone Jack Plug Y Splitter Cable Combiner