I don't have a "mm" ruler ... but these cases are exactly the same size as single blu-ray cases that come standard on those purchases. That is why I purchased these, because I wanted to add some of the older matching title DVDs to the blu-ray versions I've made lately. I have some blu-rays that have 3D covers and some that have "collectable" poster board covers and I didn't want "larger" replacement boxes that won't fit into those special covers. These were perfect.
Yes and no. Each case can store 2 discs, and there are 10 cases in this product. So while you can store six discs with this set (either as 3 cases 2 discs each case or 6 cases 1 disc each case), you can't store 6 discs in a single case.
I've purchased others, and although they had clips inside the case, there was no clear membrane on the outside of the case (front to back, including the spine) to trap/hold art and title cards, etc.
Yes ... these Dynex blu-ray cases have both the clear plastic film to hold the paper art work covers and they have the clips inside to hold any other paper information you would like included in your cases.
Memorex and other manufacturers sell single and double 7" high DVD storage cases in clear plastic which also hold artwork inside and outside. I have stored both SD and Blu-Ray discs in these cases with no issues. They are slimmer (7mm) and save more space in my bookcases.
These cases are meant more for people who would like to have a more uniform set. For example, I bought these so I could take my 007 movies from the 50 year collection and put them in these cases and set them easier on my shelf, instead of having the 50 Year collection take up so much space.