What it does

A container desiccant controls the air in the box. It does nothing for the air already sealed inside the primary pack. Silica gel goes in there: it adsorbs the water vapour trapped at packing time and whatever crosses the barrier during the voyage, holding the relative humidity inside the pack below the level at which mould, corrosion or caking start.

How it is dosed

The quantity depends on the barrier — an aluminium foil bag, a polyethylene liner and a plain carton behave very differently — on the free air volume and on the days of protection required. The sachet goes inside the sealed pack, never beside it.

Key features

• Type A silica gel, transparent spherical beads
• High adsorption capacity from its very large internal surface area
• Chemically inert, non-toxic and easy to dispose of
• Can be regenerated by heating without losing capacity

Technical specification

Typical use

Electronics and optics, leather and textiles, dried foods, pharmaceutical and diagnostic packs, metal parts and tooling.