I recently gave a trial to the Extrema Ratio KREIOS
Here the specs of the knife (from ER site http://www.extremaratioknivesdivision.eu/english/index.html):
BLADE LENGTH: mm 300
TOTAL LENGTH: mm 455
BLADE THICKNESS: mm 6,3
WEIGHT: g 650
HANDLE MATERIAL: FORPRENE
BLADE STEEL: BOHLER N690
BRUNISHING : MIL-C-13924
The KREIOS was designed by ER in collaboration with Daniele Del Canto, survival instructor at F.I.S.S. (Federazione Italiana Survival Sportivo e Sperimentale)
This knife reminds the "Parang" style, with some differences...
...in fact, we are speaking about a 6,3mm thick blade and 650 grams of a knife, so actually is more a a blade to cut down trees than shrubs or thin greens
I cutted down a 7,0 cm diameter Acacia
as you know Acacia's wood it's really hard, anyway 4-5 cuts were enough to cut down the tree. The KREIOS it's an heavy knife and well forward balanced, so you need a strong wrist and forearm to work with it.
It's possible anyway to improve the control for "more accurate" tasks like pointing a stick, forwarding your hand and placing your index finger on the finger-groove
but you need to be careful, 'cause handling the knife this way the sharp edge it's very close to you index finger
The "standard" way to handle the knife it's like this
please note how much the handle is long, this allow you to handle the knife with a 1 and 1/2 hand (like a sabre i.e.) if you want to improve the power. The handle material (Forprene) provide a good grip, the shape of the handle it's enough comfortable.
Fit and finish of the knife are fairly good, let's say enough for a "camp" knife
How about the sheath. Well, with three different buttons to secure the knife, a lot of pals for M.O.L.L.E. carrying options, a hole for water-drainage, I may say it's a good sheath
You also have the chance to carry the KREIOS at your belt, I doubt you will carry it this way due to the wheight, anyway you may if you want to...
Needless to say, after two days of jobs the blade of the KREIOS was sharp exactely at the beginning
So, how about the new ER KREIOS
well, this is a "built like a tank" camp knife, useful for some real heavy tasks. Having a 6,3mm blade you should be enough safe that the knife is virtually unbreakable. Nice cutting efficiency too, I should like a convex grind instead a full-flat grind, but that's me. The handle it's enough safe and comfortable. Good job by ER on the sheath too, it's well made and with a lot of differents carrying options. I do not like the heaviness and the steamed balance of the KREIOS, this tires in fact wrist/forearm in few time, and bring precise tasks a pain. I suggest the KREIOS to someone who want a very powerful knife for heavy tasks, or someone who want a big knife instead an axe on the woods. If you want to take with you the KREIOS on the woods, I recommend to carry a multitool too for the more precise jobs you requires.
PROS: built like a tank, enough comfortable handle, well made sheath.
CONS: too heavy for some long jobs.