Acoustic filler should be a staple of any audioholics shopping list and this inexpensive inert filler from Custom Design is made from dense material to draw out the very best performance from your speakers. As a simple guide to follow Custom Design recommend at least 2 bags of Inert Filler per 600mm column if it is not supplied as standard. Please be aware that we have found over mass loading can have a detrimental effect on the performance of your speaker removing any benefit especially to the bass frequency. 8 individual bags Supplied.