Arcadex

A small, rectangular tablet resembling a pocket mirror, an Arcadex contains a library's worth of information for those skilled enough to use it.

As a bonus action, you may point the Arcadex at a specific creature, object, or location, and make a Intelligence (Arcana) check.  You may then ask a number of questions about the target, depending on the results of the check.

10 or higher: One question

15 or higher: Two questions

20 or higher: Three questions

The answers are displayed in the mirrored surface of the Arcadex, along with a general name for the target. These questions must be about general knowledge obtainable by research, not specific questions about that exact target (for example, if pointed at a human NPC, it will identify them as "Human" and answer general questions about humans, but it contains no personal information about that NPC).  Creatures under the effect of the Disguise Self spell or similar effects are identified as the creature as which they are disguised. Similarly, the Aracadex reacts to illusions (such as those created by the minor illusion or silent image spells) as if they were real.

Answers about the statistics of the target may be given in the form of a range, as decided by the DM.  For example, asking "What is the AC of that creature?" may prompt the answer "Creatures of that type typically have an Armor Class between 12 and 15".

At the DM's discretion, information about a target may be missing or corrupted.  In this case, the display reads "No data found."