Amazon.com: 300W 3 Channel Air Cooled Subwoofer Power Amplifier Board 2.1 High Power Amplifier Board : Electronics
Infinity Primus 3000A 300W RMS Power Compact Mono Subwoofer Car Amplifier System Bundle with 12" 1200W Max Power High-Performance Car Audio Subwoofer and Amplifier Wiring Kit - Road Entertainment
300w Subwoofer Amplifier Board Low Pass Filter Subwoofer Pure Home Theater Active Subwoofer Amplifier - Home Theater Amplifiers - AliExpress
Bash 300S Digital Subwoofer Plate Amplifier 300W RMS
Monoprice 300-Watt (150w RMS x2) Studio Audio Amplifier - Monoprice.com