Desiccant cartridges for precision, electronic and optical equipment

Desiccant cartridges are used in sensitive instrumentation controls and in other highly sensitive optical and electronic equipment – particularly military applications – to protect against moisture, corrosion and fungi. The cartridges comply with the German Armed Forces technical delivery specifications (“Technische Lieferbedingungen”) TL4440-0007 (VG 95239), and have a NATO Stock Number (NSN).

Residual moisture which exists even in environments of extreme impermeability, as well as moisture that enters as a result of a leak, can condense through cooling, causing rusting or fungi, which is in turn particularly harmful to glass, reducing its lifespan. This is where desiccant cartridges come in.

Desiccant cartridges – The desiccant

In accordance with German Armed Forces specification (“Technische Lieferbedingungen”) TL 4440-0007, the desiccant cartridges are filled with a 4Å molecular sieve.
The distinguishing feature of molecular sieves as desiccants is their particularly fast adsorption rate at low relative humidity (under 50% RH).

Other types of molecular sieves (3Å, 5Å, 10Å/13X) or silica gel may also be used as desiccants in the various cartridges to suit your specific purpose.

The optimum effect

The following points are important in ensuring optimum cartridge use and effect:

  • The component assemblies must be tightly sealed
  • Openings must be sealed, as the drying that occurs inside the equipment creates a drop in pressure, making it easy for new moist air to potentially enter
  • All parts should be clean and dry, and not contain any residual moisture
    (N.B.: Plastic parts can have a residual moisture of 3-5%!)

Desiccant cartridges – Casing and protective cover

The desiccant cartridges come with a 40% moisture indicator, which enables you to precisely check the relative humidity inside the casing without having to remove the cartridge. Users can thus promptly replace the cartridges before any corrosion occurs.

The cartridge’s black case and transparent window are made from high-tensile plastic (polystyrene), while the cellulose filter facilitates targeted diffusion of water vapour so that the desiccant can adsorb moisture efficiently.

The desiccant cartridges are additionally screwed into special, transparent, VG 95239-compliant protective covers to prevent premature moisture adsorption during delivery and storage.



The desiccant cartridges are additionally delivered in sealed protective packaging to ensure none of their effectiveness is lost during transportation and storage. For optimum shelf life, store the cartridges in their original heat-sealed packaging in a dry place at room temperature.

Shelf life

Standard as per TL 4440-0007:  In an aluminium can: Up to 60 months

Optionally in a poly bag (poly bag as per DIN 55473): 12 months

Optionally in an aluminium-composite bag (aluminium composite as per TL 8135-0003): 24 months

Weight | Dimensions

Desiccant cartridges made from robust plastic (polystyrene), with window and moisture indicator for 40% relative humidity at the top.
The cartridges’ fill weight may fluctuate due to the desiccants’ varying density.

 Contact us – if you require different sizes or dimensions,we’ll be glad to advise you.

NATO Stock-No.Nominal size*ThreadMinimum fill weightInstallation length
4440-12-158-52622,5M 16 x 1,5 mm0,35 g molecular sieve15 mm
4440-12-158-5263  5M 16 x 1,5 mm0,7 g  molecular sieve24 mm
4440-12-158-526410M 16 x 1,5 mm1,5 g  molecular sieve50 mm
4440-12-175-408710M  24 x 1,5 mm1,5 g  molecular sieve17 mm
4440-12-175-408625M 36 x 1,5 mm3,5 g molecular sieve16 mm
4440-12-158-526525M 24 x 1,5 mm3,5 g molecular sieve35 mm
4440-12-158-542950M 24 x 1,5 mm7,0 g molecular sieve70 mm
4440-12-390-3594100M 36 x 1,5 mm14 g molecular sieve45 mm


*   A nominal size of, for example, 100 denotes the total capacity of a device with max. 100 dm3. The desiccant cartridges stipulated in the German Armed Forces technical delivery specifications (“Technische Lieferbedingungen”) (TL 4440-0007) are tightly screwed into protective covers, securing the top of the cartridge and the cover.

Subject to technical changes.


Consulting | Service | High availability

TROPACK provides desiccant bags, desiccant cartridges, desiccant capsules and aluminium-composite film for a wide range of applications.
Custom designs tailored to your specifications are also available. Contact us for advice:

Downloads (PDF)

TROPACK – you can count on us

TROPACK products comply with the highest quality standards according to DIN 55473 (12/2015). Our desiccants meet the relevant requirements established by the European Union (e.g. EC 1935/2004) and the US Food & Drug Administration FDA (e.g. 21 CFR part 175/part 177).

TROPACK quality standards are regularly verified in the form of DIN 55473 and ISO 9001 certifications.That’s something industry, the retail market and consumers alike can count on. TROPACK desiccants are food-safe, contaminant-free, odourless and renewable. (We expressly refrain from using dimethyl fumarate (DMF)!)

We’ll be glad to answer any questions you may have!

German-quality desiccants

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