If you have vintage razor blades or a straight razor this is a handy piece of kit. It will sharpen vintage double edged blades, single edged blades and also straight razors. I did a quick test on a Segal razor blade (these are not available for the Segal vintage razors anymore) and I noticed significant improvement in the shave with only a few strokes. As with all sharpening techniques I'd say one has to experiment with this stone a bit to achieve best results, as a very light action had the best results on this specific blade, I possibly gave it a quick micro-bevel rather than honing/polishing the existing bevel, but there was no time to figure out the what and how. Reading up a bit on angles and bevels and lots of experimentation will certainly help to have you use this stone at its optimum, don't give up on it if first you don't succeed, sharpening and honing is a skill that comes with practice, experience and patience.
Modern blades have a reputation not to hone on the various devices out there, and they are so cheap there is not really reason to do this unless you want to isolate yourself from the rest of the world until you die, but if you buy this stone for your vintage blade, why not experiment on new blades also, you might just find the key to honing modern blades and become the world's first Double-edge-Honemeister!
This little stone is in great condition.