1. The product is packaged in a strong transparent plastic box with a specification label, which is easy to store and easy to use. 2. Made of carbon steel material, with anti-oxidation surface, not easy to rust, and long service life. 3. Function: Mainly used to reduce pressure and friction, prevent leakage, isolate, loosen or disperse pressure. 4. Scope of application: applicable to household and commercial electrical appliances with thread/bolt type connection, electrical connection for automobiles and ships. 5. Surface treatment: oxidation and blackening 6. Material: 8.8 grade carbon steel 7. Product specifications: M2Inner diameter: 2mm Outer diameter: 4.5mm Thickness: 0.5mm M2.5Inner diameter: 2.5mm Outer diameter: 5mm Thickness: 0.5mm M3Inner diameter: 3mm Outer diameter: 7mm Thickness: 1mm M4Inner diameter: 4mm Outer diameter: 9mm Thickness: 1mm M5Inner diameter: 5mm Outer diameter: 10mm Thickness: 1mm M6Inner diameter: 6mm Outer diameter: 12mm Thickness: 1.5mm M8Inner diameter: 8mm Outer diameter: 16mm Thickness: 1.5mm M10Inner diameter: 10mm Outer diameter: 20mm Thickness: 1.5mm M12Inner diameter: 12mm Outer diameter: 24mm Thickness: 2mm 8. Product composition: M2 x 120 PCS M2.5 x 120 PCS M3 x 120 PCS M4 x 120 PCS M5 x 70 PCS M6 x 50 PCS M8 x 50 PCS M10 x 22 PCS M12 x 12 PCS