Premium plastic: made with high quality PE plastics, sturdy, difficult to deform. The plastic hexagon nut cover is corrosion resistant, does not age, prevents ultraviolet rays with good low temperature resistance, light weight, good toughness, and protects nuts and bolts. . Protection Bolts: These PE hex nuts cap can protect the bolts from rust water, dust, etc.,reduce dust pollution and rain, prevent bolt corrosion, beautify the appearance,thereby extending the life of the bolt. . Many Sizes: 145 sets, M4 x 50, M5 x 30, M6 x 20, M810, M10 x 20, M12 x 15. Black, large number is enough for your daily use,for hexagonal bolts and nuts . With a Storage Box: With a transparent plastic box, it is easy to store and carry, clear, easy to find.With this,you can find a suitable nut cap, you can find the appropriate nut cover quickly. . Wide Application: Suitable for machine equipment, petrochemical, valve, gas pipeline, bridge base guardrail, street light and other places. Provide external nuts and bolts to prevent weathering and damage. .