Bluetooth + MP3 Modes + Shokz App – Stream Bluetooth music and podcasts, or listen phone-free with internal MP3 storage for up to 8,000 songs. Toggle between modes and tailor your audio experience with the Shokz App. Underwater use is limited to MP3 mode due to Bluetooth signal disruption by water. IP68 Waterproof Rating – With a triple-sealed design, OpenSwim Pro is fully sweatproof and can be submerged in water up to two meters deep for two hours, for built-in MP3 audio play while swimming. Open-Ear Comfort and Connection – Our headphones are designed for enhanced safety and extended listening. Remain engaged with your surroundings while enjoying premium audio, in or out of the water. 9 Hours of Music & Calls – OpenSwim Pro technology delivers up to nine hours of continuous battery life, plus a 10-minute quick charge to immediately prepare for up to 3 hours of listening time. Secure and Stable Fit – Engineered for a slim, lightweight, ergonomic fit that stays comfortably in place through any workout and integrates seamleassly with swim caps and goggles or sunglasses and bike helmets.