My english is not good. I also want to be part of my experience with progen. They are very fragile. To stick labels is very difficult. One side is very flat and no worries. But the other side, there is a small difference in height which makes the gluing very difficult. Over time, the lable will peel off with the fingernails. Another concern is that there are chips where the edge is beveled and others where the edge is not beveled. I bought them a few days ago and will definitely be returning them.