Headphone Amplifiers descriptions： We use high-quality raw materials, all materials are very suitable for the product, please rest assured to buy. Ultra-small, Volume Dynamic Microphone-pre Amplifier Board. Features: Ultra-small Volume Dynamic Microphone Amplifier Board,two-channel Design Suitable for a Single Lithium Battery-powered,using AD828 Fever Op Amp Chip Suitable for Low Voltage Power Supply (3.7-15V) If You Only Used One Channel,the Other Channel Needs to Short-circuit the Input with GND Specifications: Size:3.2x2cm/1.3x0.79inch Compatible Audio & Video Equipment Style: Stage Equipment Model Number: 1AA700402 Dimensions (WxHxD)): 3.2x2cm/1.3x0.79inch Weight: 10g Package: No Item: MIC Preamp Module Working Voltage: DC3.7V-15V Package List: 1 * AD828 Stereo Dynamic Microphone Preamplifier Board . Products number : SOMONO94873 Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.