This hat brim "wire" is transparent plastic memory wire that measures 1.5 mm in diameter, and comes in a 20 yard roll. This diameter is similar to #19 gauge millinery wire. This wire is lightweight and washable and perfect for working with windowpane sinamays or other lightweight or light colored materials where a metal wire made be too visible or add too much bulk. It is often used in hat brims to create shapes or for support.