Kicker CXA4001 400 Watt Mono Class D Subwoofer Amplifier
Rockford Fosgate Prime R2-250X1 Mono subwoofer amplifier - Walmart.com
Amazon.com: Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer Rated 100W MAX : Electronics