Princetons Aspen combines several important benefits to artists: the brush retains its shape for control and placement of color, paint releases and glides evenly off the synthetic hairs. The brush can be used with all acrylic and oil paints including water-soluble oils. The non-glare ferrule makes Aspen™ perfect for outdoor painting. A beautiful brush only surpassed by its performance. Features – Next Gen Synthetic, Best release of color, Retains its shape for best color placement. Brush sizes – The length and width of brushes given shape and size may vary by brand as brush sizes are not standardized. Most fine art brushes are handmade and as such some variation is expected even among brushes from within a single brush line.