I have used both variants (0.5 & 0.7mm) of this product. Both variants of this pen has different attributes. 0.5 is reasonably dark and looks neat and crisp. Does not leave impressions on the other side of the page. 0.7 gives you a bolder look and stands out. Both these pens are a joy to write with and glides smoothly on paper. I have been using these for the last 2.5 years and never felt the need to switch brand. Unfortunately, this model has been out of stock in flipkart for quite some time.