Technical data Spec. D* H* T ( mm) Number per m³ Bulk density ( kg/ m³ ) Surface area ( m² / m³ ) Free volume ( % ) F factor ( m-1) Dg16 16* 16* 1.1 112000 141 188 91 249 Dg25 25* 25* 1.2 53500 150 175 90 239 Dg38 38* 38* 1.4 15800 98.0 115 89 220 Dg50 50* 50* 1.5 6500 74.8 112 90 154 Dg76 76* 76* 2.6 1930 70.9 73 92 94