Pre-cartridges of anhydrous sodium sulfate crystals from 10 to 60 mesh, type Jumbo, for retaining moisture.
Quantity of Na₂SO₄: 1 g

Pre-cartridges of potassium iodide, type Large, to reduce the interference of ozone on the sampling of aldehydes, especially formaldehyde.
Quantity in potassium iodide: 300 mg