Knafs - Mini Pocket Knife Sharpener - Diamond Stone, Two-Sided Grit - 600 (Fine) and 400 (Medium)

Slide it in your wallet. Works great on fishooks too. Sorry for spelling, I lost my glasses.

Update: I reached out to Knafs and without any questions they sent me a new sharpening stone. This be one is perfect, and Knafs prices once again their customer service is priority. So if you're looking for a pocket on the go sharpening stone, this is a great one. So this seemed like the perfect tool for on the go sharpening needs. It was compact, lightweight and had both a course and fine surface for sharpening. I own a number of Knafs products and have universally loved them. But this sharpening plate in particular has a flaw, that is perhaps only a problem on mine. On the fine side of the sharpener there are a number of rough spots, and one in particular (attached picture) that basically makes the fine unusable. It would seem the QC missed this and now this piece is useless as all it does is mar the edge because of the jagged piece sticking out. Unfortunately I purchased this for an on the go knife kit and didn't try to use it until my 30 day return window was up. Oh well, hopefully they can fix their QC on these.

This sharpener has double-sided grits in a convenient carry format. I have one for my blade maintenance travel kit and it works perfectly to maintain my blades. The cost surprised me when I saw the quality. I recommend this sharpener wholeheartedly.

This is a nice compact knife sharpener to bring with you while camping backpacking. We’re doing anything else where you need to lighten your load. One side is 400 grit while the other side is 600 grit. I would give this five stars if it wasn’t for the fact that mine is slightly defective. The 600 grit side the grit fades away on the left-hand side and become smooth regardless it will still work well and most people probably will not get one like this.

I purchased this with the Knafs leather strop and I am equally impressed with both, so my review of both will be equally...almost identical. Quality tool! It's the perfect size for a get home bag. I used it in conjunction with the Knafs leather strop, and my knife came out razor sharp. Seriously impressed with the value in the small form factor.

This is a great little knife sharpener. Does a great job quickly bringing a sharp edge to any knife. Handy to have in pocket or belt pouch.

Decent size for a glove box or pack. Hopefully it breaks in and loses the grit contamination, and clumped up particles.

Pocket size and perfect for touch up sharpening.