Amazon.com: PRV AUDIO 8 Inch Midbass Speaker 8MB450-4 v2, 450 Watts Program Power, 2 in Voice Coil, 4 Ohm, 225 Watts RMS Pro Audio Mid Bass Woofer (Single) : Electronics
Amazon.com: JINGERL 50W 4Ohm 8Ohm Car Subwoofer 4 Inch Woofers Speaker in Car Bass Speaker Long Stroke Loudspeaker for Automotive Sound Box IPC (Color : 1 pieces-4Ohm) : Electronics
55-4610 - 4 Inch 20W 8 Ohm Full Range Dual Cone Speaker: Amazon.com: Industrial & Scientific
JINGERL 1Pcs 4 Inch Audio Speaker Driver HiFi 4 8 Ohm 30W Full Range Altavoz Bookshelf Loudspeaker DIY Home Theater Amplifier (Color : Round 8Ohm 30W, Size : 4") : Amazon.com.au: Electronics