This is a Parallel Marking Tool for Woodworkers but can be just as useful for Knife Makers. These are used to layout wood but also make a nice scribe for the knife maker. These use a heavy 5mm (.175") carbide with a nicely ground flat angle. The carbide is secured to the slide bar with a stainless thumb screw. The base is made of anodized aluminum. It is approximately 1-15/16 tall by 2-3/8 wide by 3/4" thick. The flat angle grind of the carbide allows the scribe to close to zero. You can use either side of the aluminum base. The slide bar is made of stainless steel. It is 9mm in diameter (.313") and has a 9" (230mm) travel range. The scale is marked in both centimeters and millimeters. A brass thumb screw holds the base secured to the slide bar. The brass screw prevents the slide bar from being marred by the thumb screw.