Unique concept, but poorly executed

I typically use a liquid liner every day and I like to experiment with new types so I thought this would be cool to try. The tip has a little wheel on the end that’s supposed to glide on in a nice sharp line; However, this was not the case. The product did not come out consistently from the bottle and as such it was difficult to create consistent and straight lines every time. It is a cool concept though, if they could get it to work! At least the colour was unique!