Mono-to-Stereo 3.5mm 2-Conductor to 3-Cond Adapter
Stereo Vs. Mono: 1/4'' Guitar Cable Keyboard Drum & PA - Cable Assemblies - Electronic Component and Engineering Solution Forum - TechForum │ Digi-Key
Mono Vs Stereo Sound - The Difference And Why It Matters
Amazon.com: Musiclily 6.35mm 1/4 Inch Male Mono Plug to 3.5mm 1/8 Inch Female Audio Mic Professional Headphone Jack Converter Adapter Microphone Accessory, Black(Pack of 4) : Electronics
Amazon.com: 3.5mm Stereo to Mono Adapter, 2 Pack 3.5mm 1/8" TRS Stereo Male Plug to 3.5mm 1/8" Mono Female Jack : Electronics