The Dual Change Eyeliner is essentially a liner where you are able to draw both a precision line and a thicker line. How the product works is that when you place it flat on one side, the brush allows you to draw a precision line but as you turn it 90 degrees (clockwise/counter-clock), it reveals a broader surface for you to draw a thicker line. There isn't any twist button to dispense the product so you basically just keep drawing on your eyelid to the desired effect as it dispenses product sparingly so you have better control.
It has drier consistency as with most eyeliners of this type and it dries fast, which for people like me who are always rushing in the morning is desired. Pigmentation wise is on the milder side which I find looks like a charcoal-brown and it's definitely a more natural eyeliner for daily wear. Without a primer, this lasted me about 3 hours as I have very oily lids but even with a primer, this didn't stay on my lids the whole day which was disappointing as I did like to use this as a daily eyeliner for school. I paid about USD$6 plus shipping on gmarket and overall, I find that it's just a decent product that might be slightly gimmicky. There are definitely better liners out there with better pigmentation but if you need a toned down, natural looking eyeliner, this would be a satisfactory product.