You can pull it quite thin and still have a good, solid black stringer. Like most standard black boro glasses, Knight Rider is a dense black that likes an oxy environment, and can gray out a little with reduction. However, batches since 2012 have been more resistant to the graying that is inherent to blue-based blacks. In the photos here you can see it next to our dense smooth Whiteout, and the Mighty Moss. On the blown bubble, the Knight Rider went OVER the edges of the Mighty Moss, and completely masked the aventurine green, even though it was blown out fairly thin.