Fiio a1 portable headphone amplifier the a1 utilizes a sandblasted aluminium alloyed chassis for a durable modern appearance and comfortable handholding a transparent removable back clip adapts the a1 to different usage scenarios in style plug and play instant audio improvement with higher power hi fidelity output than smartphones the a1 satisfies your need for more sound quality and quantity high quality electronic volume control the a1s volume buttons are made of alps microswitches for sens