Metallic Ribbon tinsel/mylar. Because it is waterproof it is great for outdoor functions.
If you look closely at the picture you will see that the edges of the roll will be a bit rough because it is impossible to cut through the roll without getting a little roughness, but overall that shouldn't be noticed and you will have a very beautiful sparkly attraction to add to your decorations for any special occasion.
Because we cut these rolls it is difficult to get an exact measurement width. For example if you order a 3 inch it may be 3!/2 inches wide the same with the other widths. It will never be narrower but may be a bit wider so if you need to order an exact measurement  we can't guarantee that. 
This product is a mylar metallic film and is also used in fishing lures. It won't dissolve in water and it will sparkle as the flashabou as it is called is pulled through the water.