Amazon.com: Bluetooth Audio Cable, KZ Earphone Wireless Replacment Cable for KZ ZST ED12 ZSR ZS10 ES3 ES4 Headphones : Electronics
KZ bluetooth cable mod. I didn't like the original wire with the $10 BT adapter (too long and rigid) so I soldered on the original harness. Will post some pics to imgur :
KZ Bluetooth cable review: do away with wires - Soundphile Review
KZ AZ09 Bluetooth 5.2 Ear hooks | Fast worldwide delivery!
Upgraded KZ ZSN with Aptx HD Bluetooth 5.0 : r/headphones
Amazon.com: KZ AZ09 PRO Bluetooth 5.2 Module IEM Bluetooth Adapter Waterproof Ear Hook Extra Long Battery Life Bluetooth Cable for KZ ZS10 PRO/ZSN Pro X/ZSN PRO/ZEX PRO/AS16/ZAX/DQ6 /CCA CA16 /C12/CRA(C pin) :
KZ Bluetooth in-Ear Headphones Cables with Microphone Replacement for (MMCX Connector) Headsets & Accessories - Newegg.com
KZ Wireless Bluetooth Module Upgrade Cable for ZST/ED12/ZS3/ZS5 High Fidelity Earphones
KZ ZS5 85cm Bluetooth 4.2 Advanced Wireless Upgrade Module Headphone C
Amazon.com: KZ Bluetooth in-Ear Headphones Detachable Cables with 2 Pins and Microphone Replacement for KZ ZSN/ZSN PRO/ZSX/ AS12/ AS16/ ZS10 PRO : Electronics
Amazon.com: G.K KZ Upgraded Bluetooth Cable 0.75 MM C PIN IPX5 Waterproof Bluetooth 5.0 Noise Reduction Bluetooth Cable CSR8675 Chip for kz Earbuds ZAS ZS10 PRO ZSN PRO AS16(C Pin) : Electronics
KZ Bluetooth cable review: do away with wires - Soundphile Review