Thin Wooden File 240/240 grit Harmony, Art.72085 Used for refining and finishing any artificial nail surface. Hand & Nail Harmony s file collection is manufactured with superior paper resulting in a long lasting file and a much easier application for the technician. These files are going to last three times longer than the competitors files. The Hand & Nail Harmony files have a custom shape for fine detail cuticle work and a wider base for surface filing.