Terms of Reference

There are a lot of terms on our website with which you may be unfamiliar as they are rarely used outside of the bedding industry. We try to define these terms as they arise in our articles and duvet guide, but, for your convenience, here are a select few terms of reference relating to duvets and down.


CUIN stands for Cubic Inches Per Ounce. It is one way to measure the fill power of down.

Down Cambric

A down-proof fabric (one which keeps the down inside) that can serve as the casing for a duvet. Cambric fabrics are light and tightly woven.

Down Classes

Down is divided into classes signifying its quality and therefore suitability to be used in a duvet. At Downduvet.co.uk, all of our duvets are filled with the very best, Class I down. Our duvets are all either 100% down or down with a maximum of 10% feathers.


Eiderdown is gathered by hand from eider duck nests at the end of the breeding season. Eider ducks live around the northern coasts of Europe, North America, and Eastern Siberia. Their breeding area spreads from the Arctic Circle, down to more clement zones such as Scandinavia, Scotland, Denmark, Iceland, and Eastern Greenland. Eiderdown is the most exclusive and sought after variety of down.

Fill Power

Fill power is a measure of a down’s elasticity, indicating how well it retains air and its efficiency as an insulator. The higher the fill power, the less weight in down you will need to keep warm.

Mako Cambric

Mako cambric is a woven fabric made of Egyptian Mako cotton. Duvet covers made of Mako cambric are very light and airy.

Mako Satin

Mako satin is a fabric made of Egyptian Mako cotton and is woven with satin thread. This makes one side of the fabric (on the outside of the duvet) exceptionally smooth.

Ne Value

We use a fixed-weight system to determine the quality of duvet fabrics. The Ne (Number English or cotton count) value of a woven fabric indicates the delicacy of the thread. The yarn becomes finer as the count number increases. A fabric with an Ne value of 1 would use one pound of yarn if it were extended to 840 yards in length.


To ensure that no down escapes from the edge of the duvet, the fabric casing must be properly sealed. A decorative matt edging, a shiny decorative edging, or an elegant double seam can be used to accomplish this.

Please visit our frequently asked questions to learn more.