I like my knifes sharp, so I am using a whetstone. The Fällkniven D3 is a great whetstone though it is a little bit small. You can easily cut yourself while sharpening your knife. With this little holder you can now safely use your whetstone without accidentally killing yourself. The holder comes in two parts. The handle is a press-fit and has to be inserted into the main plate. If it does not fit try scaling the handle a little bit before printing. Use glue to keep the handle in place.