Features: 20 pieces produced from precision profiled austenitic stainless steel wire wound into a helical spiral, free running inserts have a spring like appearance. When installed using any one of a variety of manual or automatic tools they provide strong permanent internal threads which resist heat and corrosion. Once fitted their position is maintained by the action of radial pressure between their coils and the flanks of the tapped hole. Widely used in steam turbines, electronic communications, computers, lamps, mechanical equipment, radiators, and 3D prints equipment. Specification:Material: 304 Stainless SteelOuter Thread Dia: 4mm/0.16"Inner Thread Dia: M3 x 0.5mmOverall Length: 2mm/0.08"Main Color: Silver ToneMetric Dia.: 1DFit Drilling Diameter: 3mm/0.12"Package Content:20 x Wire Thread Inserts