Duvetyne (Commando Cloth, “Duvetene”,”Duvy”, “Duvetyn”) however you want to spell it, Duvetyne is made from 100% cotton and comes in a few different weights (8oz, 12oz, and 16oz). But trust us when we say you need the 16oz. Far too often we hear stories from crews that can still see light through their rags or flags. This is because they tried to save a few bucks and got the light weight stuff. 16OZ Duvetyne comes with one side that is soft that makes for a perfect black backing or negative fill. 16OZ Duvetyne will cut out nearly 98% of light transmission (You still won’t be able to see your hand in front of your face). It’s fire retardant, and can be easily torn from one of the sides, yet is strong enough to be used to make rags that can be as large as 300 x100 or more. Try not to get the stuff wet, the FR doesn’t like water. It also does succumb to dry rot, so even though it is one of the most durable and often used rags, it will need to be repaired from time to time. Very Easy to repair.