LD Systems Stinger G3 18" Subwoofer Dolly Board at Gear4music
Simpletune loud and clear spare wheel stealth Subwoofer recommended, Car Parts & Accessories, Audio, Video, Alarm and other Electronic Accessories on Carousell
Spare Wheel Active Subwoofer - Emphaser
Yamaha Wheel Kit for DXS-Series Subwoofers (4-Casters) SPW-1 B&H