For ANLEON S1 Personal Ear Monitor Headphone Amplifier in ear Monitoring System Description: Features: 2. It can be used on stage or in recording studio, providing flexible and convenient personal monitoring solutions for performers and recording artists. 3. High-powered headphone output with limiter protects your ears; loud enough for drummers. 4. Level and Balance/Mix controls. 5. Controls for Level and Balance. Specifications: Condition: Material: Metal Color: Black Size: Approx. 12.5 * 8.5 * 4.5 cm / 4.9 * 3.3 * 1.7 in Battery: 1*9V (NOT INCLUDED) Output: A 3.5mm Headphone Interface Frequency Response: 20hz-80khz Total Harmonic Distortion + Noise: 0.01% Signal-to-noise Ratio: >90DB Weight: Approx. 453 g Package Included: 1 x Host 1 x Adapter 1 x English Instruction Manual Notes: 1.Please allow 1-3 cm error due to manual measurement. Thanks for your understanding. 2.Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.