304 High quality stainless steel. Stainless steel is a current material of a density of 7.93 g / cm3, also called 18/8. It has good maneuverability and high toughness up to a temperature of about 800 degrees Different flat washer sizes: M2 240pcs, M2.5 240pcs, M3 200pcs, M4 140pcs, M5 90pcs, M6 70pcs M8 50pcs, M10 22pcs, M12 12pcs, M14 8pcs, M16 8pcs, to meet the different needs.It is a very essential manual tool for the family with the puck washer, the washer device spring is employed under the nut to prevent the nut from loosening. Grower washers are used for loosening, flat washers do not have a loosening function and flat washers only increase the contact surface The flat washers are arranged in a box of Storage, which allows you to easily find yourself in the series and avoid loss when needed Application: Perfect for electrical connections on household and commercial appliances, automotive uses and of marine in which the source of energy has a threaded connection / bolt-type m2 (240 pieces) m2.5 (240 pieces) m3 (200 pieces) M4 (140 pieces) M5 (90 pieces) m6 (70 pieces) M8 (50 pieces) m10 (22 pieces) M12 ( 12 pieces) M104 (8 pieces) M16 (8 pieces) The flat washers are arranged in a storage box, which allows you to easily find yourself in the Series and avoid loss when needed. Perfect for CARs Electric cords on household and commercial appliances, automotive and marine uses in which the power source has a threaded connection / bolt-type.