If you're looking for an inexpensive replacement for your Karbon this is what you're looking for, but you'll see a definite difference in quality compared to the actual premium straps that come with Garmin.
πΆοΈ Flows: Polarized Bluetooth Audio Sunglasses with Open-Ear Speakers - High Sound Quality, Long Battery Life, UVA & UVB Protection - Bruno Style (Slate Gray)
4 Review
πΆοΈ Bose Frames: Black Audio Sunglasses with Bluetooth Connectivity and Open Ear Headphones
3 Review
πΆοΈ GELETE Bluetooth Sunglasses: Music, Calls & Polarized Lenses for Men & Women
3 Review
πΆοΈ Bose Frames Tempo - Polarized Sports Audio Sunglasses with Bluetooth Connectivity in Black
7 Review