Jaybird X4 - Earphones with mic - in-ear - Bluetooth - wireless - glacier, storm metallic - Walmart.com
Jaybird X4 Bluetooth Wireless Sweat-Waterproof Headphone--Black Metallic | eBay
Logitech Jaybird X4 Wireless Bluetooth Wireless Earphones 8 Hour Play Waterproof For Sport Fit Music And Call Mobile Phone - Earphones & Headphones - AliExpress
Review of Jaybird X3: Wait for the Jaybird X4 | by Antony Seeff | Medium
Jaybird X4 Sweat & Weather-Proof Bluetooth Wireless In-Ear Headphones with Mic/Remote, Alpha Metallic