Audio and Sound Equipment Design 109 Pro Headphone by Meze Audio 109 Pro is an open-back headphone made for music listening. The design is the first dynamic open-back model from Meze Audio. A 50 mm dynamic driver is housed in a chassis that combines walnut wood, zinc, steel, vegan leather and velour, and each unit is assembled by hand. The self-adjusting headband spreads the weight evenly across different head shapes and sizes. Velour cushions surround the ears and stay soft and breathable during long listening sessions. The headphone can be taken apart and serviced, which extends its useful life.