Amazon.com: Audio Cable Replacement with in-Line Mic Remote Volume Control - Compatible with JBL Synchros S300 S300I S300a S500 S700 S400BT J56BT E40BT E30 E40 E50BT S400BT Headphone and Samsung Galaxy Android :
Cable For Jbl Synchros S300 S300i S300a S500 S700 S400bt E40bt E30 E40 E50bt S400bt Headphone Replacement Cable With Mic Remote - Audio & Video Cables - AliExpress
SCOVEE USB to 2.5mm Male AUX Audio Jack Charging Cable for JBL Synchros S300 S300I S300a S400BT J56BT E40BT E30 E40 E50BT S500 S700 Headphones Stereo Power Wire for JBL Charger Cord
Amazon.com: USB to 2.5MM Jack Cord Replacement USB Charging Power Supply Cable Compatible with JBL Synchros S300 S300I S300a S500 S700 S400BT J56BT E40BT E30 E40 E50BT S400BT Headphones (Black/60cm) : Electronics
USB to 2.5mm Charging Cable Cord Adapter for JBL S300I S300a S400BT J56BT E40BT | eBay
JBL Synchros S300 NBA Edition On-Ear Headphones SYNOE300CHI B&H
Audio Cable wire Remote MIC For JBL S300 S300I S300a S400 S400BT S500 S700 Black | eBay
JBL Synchros S300a review - YouTube
JBL Synchros S300A Premium On-Ear Headphones with Mic (White/Red)