Presented on 50g reels this Fil Au Chinois special book binding waxed linen is available in 8 sizes. The size of our binding book threads is expressed in metric number (NM), which corresponds to the number of metres per gram or the number of kilometres per kilogram. It is said that to express the thickness of a thread by a metric number is a false friend: the indicated number is proportionally the opposite of the thickness of the thread. Thus, a NM 10 is thicker than a NM 100. Check out the thread numbering explained in Madame Sajou Diary.