Sonia G Builder Three is a brush that retails for $32.00.
Sonia G. Builder Three Brush ($32.00) is a small-to-medium sized eye brush designed for packing on eyeshadow that features dyed Saikoho goat hair. Per the brand, it has the following measurements: 150mm total length, 10mm bristle length, and a 10x5 mm ferrule width.
It's easily my favorite Sonia G. eye brush that the brand has released thus far! I love a good packaging brush--rest in peace, MAC 239--and this is one of the closest I've found to the shape, density, and versatility of the 239. I'd argue this is a nice upgrade, as it has a softer feel while still being efficient at blending and diffusing color as desired. I find it picks up products well regardless of the finish or how firmly (or softly) something is pressed. It has enough flexibility to be used at any angle and with a myriad of motions, e.g. sweeping, patting, packing, pressing, tapping, or swiping.
The size isn't so large that it doesn't fit into my inner lid space, and the edge can be used easily to apply or smudge out eyeshadow on the lower lash line. I find it is particularly good at holding more product and yielding less fallout, too, when packing on more loosely-pressed shimmers or more powdery mattes.