This is a diamond file set from Goei Seisakusho. The product specifications are as follows. Product Name: GOEI DIAMOND FILES Features: Diamond particles are firmly arranged using proprietary technology, providing high polishing power and durability. Uses: Suitable for finishing, modifying, and rounding precise molds. Format: Set of files (a set of multiple shapes). Only the flat file has been used 2-3 times; the others are unused. Recommended as a professional tool for plastic model production, etc. Thank you for looking.