Amazon.com: Dual Electronics BP1204 High Performance 12 inch Car Audio Subwoofers in a Tuned Bandpass Enclosure with Blue illumiNITE LED Illumination and Plexiglass Viewing Windows and 1,100 Watts of Peak Power : Electronics
Pyle - UPLQB12 - On the Road - Subwoofer Enclosures
Alpine SBS-1041BP Type-S 10" Single Bandpass Subwoofer Enclosure at Crutchfield
Amazon.com: Pyramid 12" 1200W Car Audio Subwoofer - 2 Way Neon Bandpass Speaker System w/ Blue Lights, DC 12V Input/4 Ohm/32Hz-1KHz Freq.Res w/ Plexi-Glass Front Window & Silver Polypropylene Cone - BNPS122 :
Best Buy: R&T Enterprises 12" Single Bandpass Subwoofer Box BB-1200
4th order bandpass calculator - With subwoofer box design example