Some of our floor standing loudspeakers have the ability to be filled with particle materials from fine mineral aggregates to dedicated loudspeaker ballast. The additional mass and cabinet damping achieved can further improve low frequency response, tightening fast bass notes and defining subtle nuances and character of bass instruments. CAUTION: Not all speakers can be filled and doing so may lead to damage of internal components and the warranty of the speaker no longer being valid. If you are unsure whether or not your speaker can accept this additional mass, please consult your user manual. If you are still unsure, please submit a query to a member of our support team.