This heat set insert is made of , which can withstand long-lasting use. Features the copper and copper alloy material, which has high durability, not easy to deform. Fine workmanship, practicality. Features -Color:Golden -Material:Copper, copper alloy -Size:17.40X9.80X2.20cm/6.84X3.85X0.86in - This set contains selected nuts in different sizes, comes with a sturdy organizer for easy storage. - Made of copper and copper alloy with excellent thermal conductivity, heat resistance, good rust and wear resistance. - Copper threaded inserts for plastic are strong enough to insert easily and last longer. - Clean and burr-free, accurate and uniform, not easy to deform, to use. - Widely used in electronics, automotive, and other industries, entertainment , etc. Package list: 20 x M4x8x6 nuts 15 x M4x10x6 nuts 15 x M4x5x7 nuts 10 x M5x8x7 nuts 10 x M5x10x7 nuts 30 x M3x6x5 nuts 20 x M3x8x5 nuts 20 x M3x10x5 nuts 30 x M4x4x6 nuts 20 x M4x6x6 nuts 30 x M2x4x3.5 nuts 30 x M2x6x3.5 nuts 30 x M2x8x3.5 nuts 20 x M2x10x3.5 nuts 30 x M3x4x5 nuts