Features: Portable microphone amplifier with 28bB boost, suitable for different types of sound sources. Pre microphone amplifier, low noise floor, low impedance, effectively improves the sensitivity of dynamic microphones. Metal housing, stylish and long time use. Insert and play, simple, three connecting way, convenient and easy to use. Small in size and light in weight, suitable for studios and stage performances. Specifications: Material: Metal Color: black Size: about 9.5x1.9cm/3.74x0.75inch Product model: HD1 Increase: 28dB Connection port: 3pin male/female Power supply: 48V power supply Frequency: 20Hz-20KHz Impedance: 135Ω Suggested impedance load:>1k ohms Current consumption: is 110dB Sampling rate: 24 bit/48kbps Sound Package Includes: 1pc Microphone Preamplifier note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.