The Eclipse is a synthetic mongoose which is stiffer than sable, yet softer than bristle. 

"I love these short filberts because they are so versatile. From large passages to detail work—including a crisp line using the edge—the shorter length gives me a measure of control that is greater than what I can achieve with a long filbert. The synthetic filament is stiffer than a sable, yet is soft enough to be used for blending. I once overheard a fellow painter in a workshop exclaim: “These short filberts changed my life!” So I know I’m not the only fan of this brush."

Ross Hogin- Artist, Vashon, Washington USA, 2020.

*Available only on the longer handle*