Insulation with

Loftier Aspirations

The New Standard

Changing the Way Revolutionary Brands Think

What is DownTek™?
Here's the thing: Down is the single best insulation that exists. Period.

Its Achilles heel? Water. Rain. Sweat. Snow. Anything wet. Mother Nature designed down clusters to trap pockets of air. Those pockets insulate, keeping you warm and comfortable. Unless they get wet. Then, those air-trapping pockets deflate and lose their ability to insulate.

Enter DownTek™—Insulation with Loftier Aspirations. It shields insulating air-trapping down clusters from all wet things. It's the most amazing thing since the umbrella.

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DownTek™ is available in products from your favorite and most trusted brands.

Water Repellent Down

  • Original clean chemistry C6 formula
  • No PFOA and no PFOS
  • Available on all fill types offered by SDS
  • Lasts up to 1000 minutes on the shake test
  • Stays dry >900% longer than untreated down

DownTek PFC-Free™
Water Repellent Down

  • DWR formula completely free from all PFCs
  • Uses bluesign approved chemistry
  • Available in goose down 650 – 850 Fill Powers
  • Lasts up to 1500 minutes on the shake test
  • Stays dry 50% longer than the original DownTek™

Down is in our DNA.

The Technology

Nature + Science = Downtek

DownTek was born from a commitment to innovation and the environment.

The Responsible Down Standard (RDS)

The Responsible Down Standard (independently) certifies down against animal welfare requirements and tracks it from the source to the final product.

rds seal
"Down is great until it gets wet...but DownTek™ repels water while maintaining loft, temperature range and packability..."

Performance Test, Wired Magazine


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  • Big Agnes Bellyache Mtn SL

  • Drew discusses the features of the Bellyache Mountain SL 15° Traditional Mummy Sleeping Bag to the backdrop of beautiful downtown Steamboat Springs, Colorado.


What is DownTek™ Water Repellent Down?

DownTek™ is down that has been treated with a DWR (Durable Water Repellency) and renders the down hydrophobic. DownTek™ is currently available in either it’s original C6 formula, or the PFC-Free™ formula.

How does it work?

When regular down is exposed to moisture, the water molecules cling to the filaments of the cluster, weighing it down and forcing the cluster to collapse in on itself. Once wet, regular down loses its ability to insulate because the pockets of air that provide insulation have collapsed.

Air pockets on the down clusters of DownTek™ do not collapse. The DWR treatment creates surface tension on the filaments of the down clusters that forces the moisture molecules to bead up and roll off the down, leaving each cluster free to continue trapping warm air, thereby maintaining the ability to insulate even when exposed to water.

How is the performance of a DWR down measured?

IDFL developed the 'shake test': a global standard for the measurement of how well DWR down performs when subjected to water. They put a few grams of down in a jar along with a standardized portion of water and place the jar on an oscillating machine. Then they check the level of saturation at various time intervals until the down is completely submerged – meaning the clusters have completely collapsed and the down is no longer able to insulate.

Whereas untreated down lasts anywhere from 25-60 minutes before becoming completely saturated, DownTek™ Water Repellent Down lasts 1000 minutes, and DownTek PFC-Free™ Water Repellent Down lasts 1500 minutes. Keep in mind, this is with the down being in direct and constant contact with water for that length of time. As of yet there is no test available that can predict the length of time the down can retain it’s loft and insulating power in a real-life application like a sleeping bag or jacket, which is likely to have exposure to moisture in the form of rain or snow.

Is DownTek™ safe for the environment?

DownTek™ Water Repellent Down uses a clean chemistry C6 short-chain carbon. It is non-hazardous and non-toxic. The EPA has researched C6 short-chain PFCs and found they generally have a half-life of less than 15 minutes, so they do not persist in the environment like the long-chain C8 PFCs. DownTek is PFOA and PFOS-free.

DownTek PFC-Free™ Water Repellent Down uses a bluesign approved chemistry that contains no PFC’s.


PFOA (Perfluorooctanoic acid) and PFOS (Perfluorooctanesulfonic acid) are both C8 long-chain carbons and persist in the environment indefinitely. PFOAs are considered toxicants and carcinogens, and PFOS is a volatile sulfonamide that has been found to compromise the immune systems of both humans and animals. PFOA and PFOS can be found in Teflon, microwave popcorn bags, pizza boxes, fast food wrappers, surfactants, cleaning chemicals, floor waxes, and numerous other applications.

What is down?

Down is different than feathers! Feathers have stiff quills and while on the bird they serve as a protective barrier from the environment. Feathers on the wings can range in size from 5 cm to several inches and aid the bird in flight while also providing natural water repellency.

But down is the soft, fluffy thermal insulation found under the feathers and on the belly of the bird. While feathers have quills and are two-dimensional, down clusters have a distinct 3D structure along with tiny filaments that trap warm air.

Down is a by-product of the meat industry. Ducks and geese are a common food source in many countries, much like chicken is in the USA.

Why use down instead of a synthetic insulator?

The unique filaments on a down cluster overlap with one another, creating thousands of tiny pockets where warm air becomes trapped. No synthetic insulation can compete with the natural ability of down clusters to interlock and produce loft and warmth.

What's the difference between duck down and goose down?

Geese generally have bigger down clusters. In general, the larger the bird and the colder the climate in which they live, the larger the down cluster and the higher the fill power of the down. Duck down and feathers are generally less expensive than goose down and feathers primarily because the worldwide supply of duck exceeds that of geese because duck meat is less expensive and in higher demand overall.

Duck down clusters are usually smaller and more compact than goose down clusters, so goose down is able to achieve a higher fill power due to the larger clusters size. But that does not mean that duck down has less insulating power or can't keep you as warm as goose down. Both birds produce down clusters with the same 3D structure and air-trapping filaments, and both goose and duck down can be found in fill powers ranging from 500-850.

What's the difference between white and gray down?

There is no difference in quality between white and gray down. Both ducks and geese can be either white or grey, and there are varying degrees of both white and gray that exists depending on the specific breed of bird – even diet can have an affect on what color clusters the bird produces. White down is most often used when the end product uses a light-colored or transparent fabric.

What is down used for?

Down can be found in comforters, sleeping bags, jackets, pillows, mittens, and anywhere else lightweight thermal insulation is needed. It is important to keep in mind that the range of fill power allows for a variety of needs to be met. A lower fill power can be used in a spring/summer down comforter whereas a higher fill power jacket is more appropriate for the hiker in below-zero temperatures.

How is the quality of down measured?

All SDS factories are equipped with testing equipment to ensure each batch of down is of the highest quality. In addition to our internal quality control measures, each batch of down ordered in quantities greater than 300 kg includes a test package from the International Down and Feather Laboratory (IDFL). IDFL is a third-party testing facility that provides a wide range of tests.

What is fill power?

Fill power is the measurement of how many cubic inches one ounce of down occupies – or how much 'loft' the down can produce. More loft means more capacity to trap air and provide insulation. Larger down clusters are loftier, occupying more space and resulting in a higher fill power rating (warmer) than smaller clusters. This means that if a jacket uses a higher fill power down, less down can be used while still achieving a high degree of insulation. Fill power ranges from 500 – 1000.

The standard test used to measure fill power begins by weighing 28.4 grams of down and placing it in a cylinder tube. A specially calibrated weight is then placed on top of the cylinder that is released on a rod onto the down for 60 seconds. The outside of the cylinder is labeled with different fill power ratings, and the spot where the weight stops sinking indicates the fill power rating of the down being tested. This test is performed again 24 hours later and the results are compared and averaged. Fill power can be influenced by a variety of factors including: sitting in transit, humidity, temperature, static electricity, and how it was packaged for delivery.

What is turbidity?

Turbidity is a technique that involves measuring 10 grams of down and placing it into a special beaker with 1 liter of water. This beaker is then sealed up and vigorously shaken for 15 minutes. After 15 minutes, the mixture is strained using a special filter and placed into another long tube. The tester will visually look down into the opening of this cylinder to see if a pair of crosshairs on the bottom are visible. On the outside of this clear cylinder are markings with measurements that indicate the amount of liquid in the container. The cylinder is filled to the top where the marking is. If the tester has trouble viewing the crosshairs the beaker is emptied until they are visible from the top. 550 is an excellent level and the highest measured in the United States (150 is considered acceptable–where as some Japanese companies prefer 800). In essence, the higher the turbidity number, the ‘cleaner’ the down.

What is the oxygen test?

The oxygen test is a technique where the presence of organic materials is measured. Organic materials are found in unwashed products that come from the meat processing plants-including blood from the waterfowl. The test is complicated but basically involves applying specially measured chemicals to the same water used for the turbidity test. The lower the Oxygen count, the less organic materials that are present in the finished product. A good Oxygen test measures 4.5 or lower.

Can I wash my down product?

The key to successfully washing your down product in a home washer and dryer is using a mild detergent that doesn’t strip the down of it’s natural properties and then DRY DRY DRY! Down products should be completely dried to avoid clumping, odor, and mildew. You should always reference the manufacturers label for washing instructions since there is also the fabric and accessories to take into consideration (zippers, buttons, strings, etc), but in general, the higher the heat setting on your dryer, the better for the down.

Drying tip: about half-way through the dry cycle, put a tennis ball in the dryer along with the down product to distribute any clumps that may have occurred during the wash process.

Tennis ball tip: to keep the tennis ball from bouncing around loudly in the dryer, first put it in a thick sock. We do not recommend dry cleaning products containing down.


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