As an MQS portable system, which plays studio Mastering-Quality Sound (MQS), this is an ultimate portable hi-fi audio system. The hairline of the aluminum body, which perfectly matches the real sound, looks different according to the angle of light. The metallic black body which looks ponderous like a masterpiece made by a master craftsman, and the conflicting high-gloss back show beauty of reversal. Not the conventional hardware volume button, the minute-controlling analog volume wheel, which expresses classic beauty in a modern way, is Astell & Kern's own classic icon to impress users.