Features： 1. Bluetooth + MP3 Modes: MPOW swimming headphones adopts the latest dual-core Bluetooth 5.4 chip for faster and more stable connection. It has a built-in 32G memory card that supports MP3 audio format and can store about 8000 songs. Bluetooth doesn't work underwater, so you can switch to MP3 mode while swimming so you can listen to all your favorite music and audiobooks underwater. .