Experience superior sound quality with Sennheiser's SPORT True Wireless earbuds. Powered by True Response transducers, the 7mm dynamic audio driver provides an immersive sound experience with full bass. Customize your audio with a choice of presets and an intuitive equalizer through the Smart Control App. Adaptable Acoustic feature provides the choice of Open or Closed ear adapters, that match with special EQ modes to provide the perfect setting for your exercise. Experience a secure and customized fit with a choice of ear adapters and four ear fins, so they stay comfortably in place during any performance. The earbuds are designed with a durable, IP54-rated design to handle sweat, rain or workouts on the beach. Enjoy up to 27 hours of battery life with 9 hours of playback and 18 hours of extra power on-the-go charging via the case.