I worked a super huge Bobbi event yesterday and saw what seemed like a million women, all different ages, likes and needs but all bought one thing alike; the Ultra Fine Eyeliner Brush. It's my new BF for my lining needs. I used it all day with their Long-Wear Gel Eyeliner (LOVE) but it can be used with any formula besides pencil. One woman didn't like her gel liner because she felt it was too hard to blend, but she didn't have this brush. After showing her how easy the brush was to use for even the most un-steady of hands, she kept her return and stocked up on a few more gels liners. The width is perfect for a medium line if you use it sideways, without making the line too thick. The tip of the brush has less dense bristles than traditional brushes which make it more forgiving and great for blending.

Bobbi Brown Ultra Fine Eyeliner Brush