This beautiful thread made by DMC has become very difficult to source. It is an equivalent weight and texture to cotton perle no.12 but wears much better. It can be used in long lengths without becoming tired and fibrous. I love this thread for finer drawn thread, pulled thread, Hardanger and for textured surface whitework. It also takes dye very well and is effective as a soft string padding for finer silver metal thread embroidery.
You may also be interested in my Fundamental Whitework Techniques book and my Essential Tips for Designing and Working Fine Whitework Embroidery book.