The Blue sachets can be used in the top or directly in the waste tank. Features Resealable pack Pre-measured portion control When adding to waste tank, also add 2 litres of water for best performance Specifications Model: 040873 Camec NOT suitable for septic tanks or composting toilets 15 sachets each suit cassette up to 25 litres Slightly longer lasting than the GREEN Bio-Pak Shipping Weight: 420 grams. Shipping Dimensions: 13 cm x 18 cm x 7 cm.