Perfect to go. Versatile and captivating, the new HD 4 series offers the complete Sennheiser quality package in a series of robust, acoustically closed over-ear headsets that embellish every day with the best sound. If you are enthusiastic about the sound of the HD 4.40 Wireless, it's no coincidence. The acoustically closed construction of this headset is equipped with Sennheiser transducers, which had to take a long path of development before they were allowed to supply your ears with music. Enjoy the balanced, incredibly detailed sound with deep, dynamic bass. The HD 4.40 Wireless is about freedom of movement. Therefore: no cables. You get the latest wireless technology, with Bluetooth 4.0 and aptX codec, which guarantees reliable transmission and true hi-fi sound. Near-field communication (NFC) ensures fast and easy connection to compatible mobile devices. Telephoning, changing music tracks, adjusting the volume - with the intuitive controls integrated into the earpiece of the HD 4.40 Wireless, this is really fun. Try it out. The HD 4.40 Wireless is designed to take you wherever you go - to make you feel more comfortable. The ear-enclosing design with deep, ergonomically shaped ear cushions offers unsurpassed comfort, even for very long hearing. With its robust foldable headband, it can be quickly and compactly stowed in the protective transport bag supplied. Elegant and minimalist - with robust, high-quality materials: this is how the HD 4.40 Wireless was designed. Its slim, attractive shape not only ensures high wearing comfort, it also makes a statement for timeless class.