Amazon.com: CableCreation Aux Cord for Car, 3FT Right Angle TRRS 3.5MM Male to Male Auxiliary HiFi Stereo Cable with Silver-Plating Copper Core Compatible with iPhones,Tablet,Headphones,Speakers,Black : Electronics
Analog Potentiometer Volume Adjustable TRRS Headset : ID 3959 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits
HamiltonBuhl Flex-Phone™ TRRS Headset with Gooseneck Microphone for K-5 - HamiltonBuhl
Amazon.com: YCS basics 3.5mm Smartphone TRRS Headset to TRS Headphones Adapter (Removes The Microphone Channel) : Electronics