This is a scriber for plastic and resin. This scriber can be used in two ways: - the sharp “blade” end can be used in a manner similar to other scribers, either free-hand or running along a hard edge, such as a ruler. This removes a fine burr of material leaving a clean groove behind. The tip of the scriber allows it to work with scribing templates. The set includes three blades to replace worn or damaged blades. - the back (curved) edge of the holder has extremely fine teeth that act like a file and leave a very fine groove behind. This is ideal for scribing edge panel lines such as wing edges, fuselage spines etc but it can also be used by running it along a hard edge such as a ruler. The tool is made entirely of stainless steel. The set does not include the knife handle.