Keep case is the general term for a number of packings. As I understand it, it's anything made out of plastic with the typical "click" closing. As the English Wikipedia says: "The first products to be released in keep cases were VHS tapes" - I myself would have only used it for BluRay and DVD :D

Amaray which you are probably familliar with is only the company name of probably the largest and most famous producer of such Keepcases. However, there are a number more and they all have slightly distinct features, e.g. Viva Elite's Amaray-like Casing has less round corners, is slightly thinner and has a different Spine mechanism, there is Scanavo who produces standard Amaray-like casings but also a special kind (i've uploaded a comparisson photo here, recently), and Viva Elite has another casing named Eco, which is "ecological", i.e. they leave big plastic holes in the inside (see picture). There are even more but thos are the ones that I know of and can recognize by eye.

All of these are keep cases, which is why keep case is (or should be) more prominently used for these package type unless you are pretty sure or want to stress that a certain keep case is by Amaray.
Steelbook on the other hand is a trademark, so there is only one build type and only one company producing those (others have their own names such as Novobox, Futurepack, etc.)

EDIT: Here's the Wikipedia article

I just read it now, otherwhise I'd answer earlier:



I am not sure where exactly to do that, anymore as I've done it right away. In Germany there are different services to do that, but I guess you can also send in a copy of your passport, with your birthday on it. Once you are validated as 18+ you can access those links.

If you cannot find it, maybe someone of the team can help you - you can contact them via the contact form.

I thought it was possible with simple date of birth on profile...
However, keepcase was referred to Western Legenden series from Koch, I don't know if you know them.
The Amazon service said to me they are neither digibook-mediabook nor amaray.
The Koch service said they are keepcase in second press release.
I see on eBay that second press DVD are amaray, but I haven't seen a blu-ray edition that is not a mediabook...

This is a first press blu-ray or so I believe...