The shell of the FH3 is made of aerospace-grade aluminum-magnesium alloy. Structurally, through data on thousands of people's ears as well as going through more than 10 rounds of trials and iteration, an extremely comfortable design for the FH3 was created. In order to achieve more comfortable listening, the FH3 utilizes FiiO's patented balanced pressure relief technology, so as to ensure that the air pressure in the front and rear chambers are balanced, thus ensuring music dynamics are not distorted and thus making for stress-free listening. Meanwhile, in order to make it more comfortable to hold and grip, the FH3 is carefully adjusted from 3 different angles, which is more easy to pick up and drop down, ensuring perfect experience from every tiny facet.