Interchangeable Earhooks For strenuous exercise, you can put on ear hooks to keep them stable. Interchangeable Earhooks You can put on soft ear supports for leisure and entertainment to make your ears feel more comfortable. Wide Compatibility Adopting Bluetooth 5.1 chip & technology, MS-T20 in ear Bluetooth headphones is compatible with most Bluetooth-enabled devices including IOS system, Windows system and Android smart phones. Stereo Sound Quality Adopting bluetooth rendering technology that produce stereo sound quality and crystal crisp treble. Non-slip ear supports With ergonomic ear hooks, flexible rubber, MS-T20 offers stable fit and comfortable wearing. Even you are running fast, they still remain on your ears. Comfy & Secure Fit Adjustable & secure-fit earhooks keep the earbuds in place when moving or working out, soft ear tips and ergonomic design offers comfortable wearing experience. Equipped with 3 pairs of ear caps (L/M/S) for your choice to get the most suitable fitting. Even if you do strenuous exercise, do not worry about the earbuds will fall off.