Audio-technica's ath-ckr75bt headphones feature high-precision 11.8 mm drivers, giving excellent, efficient, audio quality with all the convenience of bluetooth wireless technology. The drivers are capable of replicating audio with a 5-40,000 hz frequency extended range. An added perk is that they come with an amplifier to increase the sound's resolution and depth. These drivers aren't being wasted on a low-quality wireless feed; audio-technica ensures that by making these headphones compatible with aptx and aac codecs, in addition to the standard sbc codec. To further help the sound quality, the headphones'housings are made of aluminium, making them extremely strong while still remaining lightweight. These housings greatly reduce any undesired resonance, creating the clearest mid- and high- range reproductions possible.one of the most user-friendly features of these headphones is that they include an in-line mic and controls. This allows for a user to control functions such as call answering, volume adjustment, and playback of music and videos through any compatible device, such as a smartphone or tablet. The headphones are cleverly designed to fit behind the neck, which conveniently positions the mic and controls to easily accessed. For the most comfortable fit, the ath-crk75bt headphones come with interchangeable ear tips in xs, s, m, and l sizes. The charging cable is 11.8" (30 cm) long. The headphones also come with a carrying case and secure-fit battery clip.