Amazon.com: DD ddHiFi All-New DJ44B Aluminum Version 4.4mm Balanced Female to 2.5mm BAL Male Headphone Jack Adapter, Audio Converter for Earphones/Headphones : Electronics
Just Hook It Up 2.5mm Male to 3.5mm Female Audio Adapter - Micro Center
HIFIMAN HE400S HE-400i (3.5mm to Dual 2.5mm) Silver Copper 6N OCC Version - 4ft | eBay
USB 3.0 to SATA/PATA/IDE Hard Drive Adapter Cable Compatible with All Computer System, 2.5'' / 3.5'' Hard Disk HDD Connector Converter Set with [Updated Version] Stable AC Power Supply - Walmart.com
PW Audio Legend II Headphone Upgrade Cable MMCX CM 2.5mm 3.5mm 4.4mm
Cable With 3.5mm Stereo Plug To Dual 2.5mm Male Compatible With Hifiman He400s, He-400i He-400i Dual 2.5mm Version He560 - Audio & Video Cables - AliExpress