Sennheiser CX 400BT True Wireless Earbuds feature premium dynamic driver technology for pure listening. Enjoy up to 20 hours of music on a single charge with an ergonomic design and four ear adapter sizes for optimal comfort and fit. Customize all functions, including touch controls, via the Sennheiser Smart Control app for iOS and Android. These headphones offer passive noise cancellation. Please note that international products may have different terms, come from abroad, and may differ from local products in terms of fit, age ratings, and language on the product, labeling, or instructions.