Feature: 1. CLEAR SOUND QUALITY: This HiFi preamplifier with low noise integrated circuits and high quality components to remove low frequency noise ensure clear sound quality. 2. COMPATIBLE: RCA input for preamplifiers to computers, CDs, telephones etc. and RCA output to digital amplifiers, active multimedia sound devices with lossless sound (excluding RCA cables). 3. SAFETY DESIGN: This preamplifier has a built in switch, circuit shock protection and overheating protection for a long life. 4. PRACTICAL: This tube preamplifier improves all the detail, transparency, immediacy, richness and tone associated with your music. 5. APPLICABLE DEVICES: The vacuum tube preamp suitable for mobile phones, computers, tablets, TVs, set‑top boxes, projectors, etc. Specification: Item Type: Tube Preamplifier Material: Aluminium Alloy Distortion: 0.03% SNR: 100dB Frequency Response: ±1.5dB (20hz-20khz) Output Connector: RCA Operation: Toggle Switch, Volume Adjustment Knob, High and Low Pitch Knob Applicable Devices: For Mobile Phones, Computers, Tablets, Tvs, Set-top Boxes, Projectors and Other Devices with Analogue Output Devices, etc.. Package List: 1 x Preamplifier2 x Electronic Tube 1 x Chinese and English Manual 1 x Power Adapter Note: This is a preamplifier, not a power amplifier or phono preamplifier, and cannot be used for passive speakers.