Silica sand that eliminates 99% of odors and doesn't need to be changed for about 4 weeks. 4.5L x 6 bags I think this price, including shipping, is a good deal. - Brand: JOY PET - Type: Silica Sand - Deodorizing Effect: Eliminates 99% of odors - Replacement Frequency: Approximately 4 weeks without replacement - Features: Less likely to scatter, cushion type Thank you for viewing.