This 1/4 inch (0.2500) round American pattern file is crafted from durable steel for reliable metalworking and shaping applications.1/4" Round American Pattern File SteelPrecise 0.2500 inch diameterAmerican pattern tooth configurationSteel construction for durabilityRound profile for curved surfaces and holesIdeal for filing curved surfaces enlarging holes and smoothing rounded edges in metal fabrication machining and repair work.