The brushes feel to me like sable, not so stiff as many nylon bristle brushes. This makes them ideal for glazing, but the longer bristle brushes are not quite so good for heavy body acrylic work because they flex and lose their shape too easily against the high viscosity paints. The shorter bristles have no problem with heavy body and are still good for low viscosity painting techniques such as glazing.
The ferules are matte metal and as such tend to stain with certain paints. The bristles clean very well. The handles are also matte, seem to be painted in almost a milk paint. They are attractive, well balanced, have a great carrying case and work very well at glazing and fluid painting, but can be used for more heavy body with some success, though if you like a stiffer brush these are not for you. I like them for what they are. I will take one star (actually if allowed it would be a half star) for the matte finishes; they are harder to clean paint off.