1)In-(1)Out S-Video, Composite Video Stereo Audio Booster (S-VIDEO) | ShinybowUSA
Build a Great Sounding Audio Amplifier (with Bass Boost) from the LM386
Passive HiFi Stereo Preamp Audio Booster Volume Controller for Power Amplifier | eBay
Orb Audio: Booster 50 Watt 2.1 Audiophile Amp - Optical In, Sub Out and Remote Control - EZ Voice Dialogue Boost and Bluetooth C
Boostaroo Headset Audio Amplifier (2x)
Orb Audio Booster Mini Amplifier and Speaker System Review - The Gadgeteer
M-Audio
Orb Audio Booster Amplifier
Booster Mini Integrated Amplifier | Orb Audio
Amazon.com: Mini High-Gain Stereo Audio Booster with Volume Control : Electronics
Shinybow S-Video and Composite BNC Video with Stereo Audio Booster Extender Amplifier SB-2809 - Walmart.com
600ω: 60k 10 Times Booster Amplifier Audio Transformer, Passive Amplification, Balanced And Unbalanced To Pt52 - Transformers - AliExpress
Amazon.com: Polarlander Power Car Amplifier Hi-Fi 2.1 MP3 Radio Audio Stereo Bass Speaker Booster Player for Motorbike Home No Power Plug : Electronics
Amazon.com: iBoost 800 Stereo Line Level Audio Amplifier Booster Amp for MP3, iPod, iPad, iPhone : Electronics