I have this one. It has medium grit (like SPYDERCO brown rods) and is pretty adequate to obtain decent working edge. If your knife is not blunted heavily or damaged you will be able to sharpen it with no contraindication.
With no contraindication doesn't mean easy in this case. Tri-Seps is pretty tricky to work with, especially for non-experienced user. The angle guide works very clumsy, in fact you have to sharpen free hand on a very short sharpening surface. This is an opposite side of diminutive size and ease to carry.
However you have a possibility to sharpen each kind of edge (plain, serrated, recurved) and additionally darts, fishhooks and another pointed tools.
Reassuming low cost and light weight I can say certainly - this is very size- and cost efficient field sharpener. If you are able to work with it - it will serve you decently.