The "V" stones or rods are OK but liek someoen else posted before, nothing will ever beat practice and skill of using a flat stone with proper angle control. I've got a couple of Fiskar pocket "V" rods that I carry in my camp gear and used to kep one with me in my kits when I was in the field. They were good enough to keep a decent edge on a sharp kinfe but useles when it came to putting an edge on a knife that needed one.
The trouble I found with them was that they would have a tendency if the angle was too high that teh edge would actually bind at the very vertex of the "V" and actually "flatten" the "razors edge" of the knife instead of actually honing it. It was OK for my K-Bar but I wouldn't use it on my Uncle Henry pocket knife. I always carried two small pocket stones with me, one fine, one rough.
We sleep peaceful in our beds because Rough Men stand ready in the night to visit violence upon those who would do us harm.......G. Orwell
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