MusEcho Burnishing Rod
This will do a quick sharpening of a knife. Just hold the knife at about 30 degrees on the rod and take a few forward strokes with generous pressure. Then turn the knife over and tilt it at 25 degrees and take two strokes toward you. Set the burr by flipping it back over and tilting it at 35-40 degrees and taking one down stroke.
This tool can be stored very compactly because the rod comes out and is stored inside the handle. It is magnetized so it stays put.
It comes in a nice leather case.