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, settop boxes, projectors, etc.Specification:Item Type: Tube PreamplifierMaterial: Aluminium AlloyDistortion: 0.03%SNR: 100dBFrequency Response: 1.5dB (20hz-20khz)Output Connector: RCAOperation: Toggle Switch, Volume Adjustment Knob, High and Low Pitch KnobApplicable 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.