QSC Subwoofer Caster Kit 
If you need to move your QSC around the stage or studio, QSC has the Caster Kit you need. This kit includes a set of four 3" sturdy casters that slip right into the base of your subwoofer. These soft wheels won't leave a mark on hardwood floors.
 
QSC Caster Kit Features:
A set of 4 casters 
Compatible with KS Series subs (KS112, KS212C), KW181, and KLA181
Designed to easily slip into the base of your subwoofer
Soft wheels won't mar hardwood floors