Originally made using a birds quill, nowadays a soft pliable yet durable polypropylene is used to house the brush head. This style of brush has become popular over the last decade with watercolourists who like expressive and loose work. Offers a massive liquid carrying capacity and must be thoroughly wet to work. Also popular for Chinese style strokes. I also make the rounded domed version of this brush for French Polishers. This style of brush is very different to use than a conventional ferrule construction.