Not my favorite... but it does what it says - KZ APTX HD 5.0 Bluetooth Upgrade Cable vs the AZ09 - YouTube
Bluetooth Cable Kz Headphones | Bluetooth Wireless Earphone - Waterproof Bluetooth - Aliexpress
KZ APTX Bluetooth cable Type "B" for KZ In-Ear Headphones with Microph – CBN Music Warehouse
Amazon.com: KZ AZ15 Wireless Earhooks Bluetooth5.2 with APTX, AAC, and SBC Transmission Mode Bluetooth Cable Earbuds Hook 2 PIN 0.75MM for kz zs10 pro zas Zax zsn pro x C PIN :