Amazon.com: 3.5mm Stereo Male to Dual 3.5mm Mono Male Audio Cable, 1ft 3.5mm 1/8" TRS Male to 2 x 3.5mm 1/8" TS Male Y Breakout Cable Splitter Adapter for Headphone, Speaker :
2-Pack 3.5mm Mono Female Jack to 2.5mm Mono Plug Audio Adapter, AV-A39-2 | eBay
hardware - Does professional quality stereo to mono conversion require a special adapter - Sound Design Stack Exchange
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
Amazon.com: 9 Inch Long 1/4 Inch Stereo TRS Female to 2 X 1/4 Inch Male Mono Y Splitter Cable : Electronics
3.5mm Mini 1/8 inch Stereo Female Jack to Dual 1/4 6.35mm Male Plug Mono Right Angle Audio Adapter Y Splitter Cable - Walmart.com
2-Cond Mono female Jack to 3-Cond Male Plug Stereo Adapter
TNP 3.5mm TRS to 2 Dual 1/4 Inch TS Stereo Audio Breakout Cable Adapter -
BesYee 4330230285 Poyiccot 1/4 to 3.5mm Headphone Adapter, 3.5mm to 1/4 Cable, 3.5mm Mini 1/8" TRS Stereo Male to 2 Dual 1/4 Inch 6.35mm Mono TS F
1m 3.5mm Stereo Plug to 2x Mono Jack Adapter Cable AUX Audio Line Splitter Lead 5055538150425 | eBay
Hosa Technology Stereo Mini Male to 2 Mono 1/4" Male CMP-159 B&H
6.35mm 1/4" Male Plug to Dual 6.35mm Female Stereo Audio Splitter Connector AU | eBay
1pc 6.35mm 1/4 Inch Stereo Trs Female To 2 Dual 6.35mm Mono Ts Male Y Splitter Adapter Connector Cable Cord 38cm - Audio & Video Cables - AliExpress
3pc 6.35mm 1/4 Inch Stereo Trs Female To 2 Dual 6.35mm Mono Ts Male Y Splitter Cable - Audio & Video Cables - AliExpress
Amazon.com: Disino 1/4 Mono to 3.5mm Stereo Adapter, Gold Plated 6.35mm TS Male Plug to 1/8 inch TRS Female Audio Connector - 2 Pack : Electronics