Amazon.com: Linkidea Replacement Audio Cable with Mic Compatible with JBL E55BT E50BT E45BT E40BT E35 E30 E65BTNC 650BTNC S700, 2.5mm TRS to TRRS Aux Cord with Inline Microphone and Volume Control (5ft/1.5m) :
Nylon Audio Cable with mic For JBL E45BT E50BT E55BT E30 Synchros Chrome Edition | eBay
JBL Synchros E50BT and E40BT Review | Techolo - Philippine Technology Outlook Blog