Review on Honing Guide for Sharpening Chisels and Planes by Troy Early

Essential when you need to sharpen a chisel and don't have a steady hand to hold it at the exact angle. It holds the blade and lets it roll across the stone, keeping the whetstone in the same place. Sometimes it's a bit difficult to get the chisel to stay in the flutes of the tool as some of my chisels are wider than the flutes, but once you snap it in it works perfectly and you can get your tools razor sharp.