Item Type: Headphone Amplifier Material: Aluminum Alloy Battery: Lithium-ion Battery 502030 (Built-in) Capacity: 250 MA Power Supply: DC 5V Interface: Approx. 3.5mm/0.1in Practical Use: Directly connected headphones for listening, can be connected to mobile phone recording Size: Approx. 65x53x25mm / 2.6x2.1x1.0in 1. HIGH SENSITIVITY: The headphone amplifier has high sensitivity, ALC automatic level control, 1000 times amplification, allowing you to hear faint sounds. 2. CLEAR SOUND: Portable headphone amplifier amplifies your voice with clear, crisp, noise-free, distortion-free sound, stylish and powerful. 3. INTERFACE IS 3.5MM: Stereo headphone amplifier directly connected headphones for listening, can be connected to mobile phone recording, the interface is 3.5mm. 4. ALUMINUM ALLOY SHELL: Microphone amplifier with aluminum shell, compact size, storage and transportation are very convenient, beautiful appearance. 5. ANTI-INTERFERENCE: The headphone amplifier ensures lossless signal as well as strong anti-interference performance, very reliable. 6. APPLICABLE RANGE: The headphone amplifier is suitable for teaching, coaches, singers, coaches, shopping malls, presentations, outdoor speeches, etc. 1 x Microphone Amplifier 1 x Power Cable 1 x Headphone Cable Please allow for some error due to manual measurement