I have many beautiful powder/mineral eye shadows that I use for liner, but they transfer or wear off easily. In the provided "cup" I mix a tiny bit of this product with the shadow powder using a liner brush, and now I have no problem with smearing, fading, or transfer. I can't see using this for anything other than shadow or liner, but I haven't tried it for any other application. The brush serves no purpose for me with this product, but again, I use this for liner with a fine liner brush. I also have sensitive eyes and skin and this did not cause any irritation.
Bottom Line Yes, I would recommend this to a friend
Put a few drops of the Lock & Seal into the small put provided. Dampen the brush thoroughly with the liquid & mix with any powder or cream makeup & apply to the face & let dry thoroughly. Remove with cleanser & warm water. For best results clean the brush after each use.