Boker plus 0509 3.5 inches from choil to tip, 440C steel. Feels like real 440C steel by the way it sharpens, showing the same stubbornness and lack of cooperation in getting sharp as opposed to, say, Super Blue, which rearranges it's own molecules and gets sharpener when it thinks you aren't paying attention. 440C would rather be a bearing than a knife edge IMO.
The knife itself is an excellently made lockback with a titanium handle, steel pocket clip and thumbstud, as well as steel screws. The Titanium body is very well made, the inside parts of the knife in general seem to be finished like you get with a higher quality knife.
Year? I don't know. Is it still in production? Who knows. What does it cost? Don't know. When did I even get it? Don't know that either but it must have impressed me given my general distaste of 440C. I'd guess hardness to be at around rc59 or so by the way it sharpens on my DMT coarse stone(s) I have used for 20 years now.
If you run across one and don't mind 440C I will vouch for it's fine build looking like a CNC machine did some precise work on it.
The Boker Plus does not have a made in Germany on the blade so I assume china. If this was made in Germany I doubt I would have bought this knife as it would be higher priced than I prefer for 440C knives, Ti or not.
https://www.boker.de/us/pocket-knife/boker-plus/classic-pocket-knife/01BO188.html
Joe