1. Using 6J5 tube, NE5532 2. The capacitor uses the 470UF/25V, and the coupling capacitor uses the capacitor 1UF. 3. The resistor uses high-precision chip resistor to a good signal-to-noise ratio of the whole machine. 4. The PCB adopts 1.6mm thick double-sided sheet, 2.0 oz copper thickness, and the whole process of tin-spraying ensures the good passing performance of large and small currents. First-class PCB quality. 5. The input and output are made of gold-plated lotus seat, which is and beautiful. The board layout is reasonable, beautiful, and the current is small. Power: DC12V2A Colour:Photo Color Material:ABS Size: 133x89x22MM (without tube height) Package Contents: 1 x Bluetooth Tube Preamplifier Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.