Amazon.com: Nobsound G2 PRO Hi-Fi 300W Subwoofer Power Amplifier Mono Channel Class D SUB Audio Amp : Electronics
Kicker 47KEY5001 Digital Signal Processor Smart Mono Subwoofer Amplifier Bass Revealer and Processor Vehicle Audio System (Black) | electronicsexpo.com
Pioneer 1-Channel Class D Mono Amplifier Black GM-DX871 - Best Buy
Fosi Audio M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply - Walmart.com