Alpine W12S4 12" 250 Watt 4 OHM Subwoofer with GTX500 Mono Subwoofer Amplifier 500 watts RMS x 1 at 2 ohms - Creative Audio
How to Match Subwoofers and Amplifiers
How to Wire a Dual 4 ohm Subwoofer to a 2 ohm Final Impedance | Car Audio 101 - YouTube
Amazon.com: BOSS Audio Systems R1100M-S Riot Series Car Audio Subwoofer Amplifier - 1100 High Output, Monoblock, Class A/B, 2/4 Ohm Stable, Low/High Level Inputs, Low Pass Crossover, Mosfet, Hook Up to Stereo :
Amazon.com: Pyramid BNPS102 10" 1000W 4-Ohm Subwoofer Sub Bandpass System with Neon Accent Lighting PB715X 1000W 2-Channel 4-Ohm RCA Amplifier Amp : Electronics
Subwoofer Wiring Diagrams — How to Hook Up Your Subs