Our 600 grit, round, spire diamond file is made of steel, which is thinly electro-plated with diamond. Because of its flexibility, this file is very durable making it extremely effective when polishing molds with very narrow and deep ridges.  This file is double-ended and measures 50mm (2") long x 0.5mm (0.02") in diameter.  Both ends are beveled at a 20 degree angle. More than 75% of the file coated with diamond. Use with our handheld, double-ended, reversible collet pin vise (820-4350 sold separately). Made in Japan.