Window or basket weave sinamay is a straw cloth made from abaca fibre. It is woven with ‘eyelets’ or ‘windows’ in the weave for an open textural finish. It is best used in a single or double layer (e.g. example of a bias brim) as more layers will make for a confusing look.
The large in the title refers to the weave pattern. This variety has larger ‘windows’ than the regular basket weave sinamay.