This special nail polish is a polish designed specially for stamping.
The brush is flat and quite wide.
12ml is the amount of polish you get.
I often use opaque in one coat nail polishes for stamping with. I have found that it easier to find a opaque in one coat dark polish whereas a white is harder to come by.
This polish is designed for stamping and I have found it works really well. It stamped opaquely and without any patchiness.
I also have been using this polish mixed in with standard polishes to create a custom stamping polish colour (tutorial here).
Here are some stamped nails I have done using this polish:
MoYou Nails - Special Nail Polish White