MATERIAL: The sealing rings are made of nitrile rubber (NBR) material, water and oil resistance, good weldability, corrosion resistance, high temperature resistant FUNCTIONAL: Sealing O-rings for repairing wiring and preventing metal-to-metal contact as well to protect wires and cables 18: DIFFERENT SIZES The sealing o-rings assortment kit includes 325 pieces with 18 different sizes, meeting your professional needs PRACTICAL: sealing washers meet most plumbing, automotive, repair needs, general hydraulic and pneumatic maintenance by providing a firm seal on any medium such as oil, air, gas and water TIDY STORAGE: rings Rubber O are stored in an organized case saves you the effort of storage and choosing the size; Variety of thickness and size are in one box, very convenient to use Features Gasket sealing washer -Color: Black, White. -Material: NBR. -Size: Black (inner diameter x outer diameter): 0.3X0.8 cm / 0.12x0.31 inch. 0.5X1 cm / 0.20x0.39 inches. 0.6X1.05 cm / 0.24x0.41 inches. 0.8X1.4 cm / 0.31x0.55 inches. 1.0X1.5 cm / 0.39x0.59 inches. 1.2X1.8 cm / 0.47x0.71 inches. 1.6X2. 4 cm / 0.63x0.94 inches. 1.8X2.6 cm / 0.71x1.02 inches. 2.0X2.8 cm / 0.79x1.10 inches. White (diameter): 0.3 cm / 0.12 inch. 0.5 cm / 0.20 inch. 0.6 cm / 0.24 inch. 0.8 cm / 0.31 inch. 1.0 cm / 0.39 inch. 1.2 cm / 0.47 inches. 1.4 cm / 0.55 inches. 1.6 cm / 0.63 inches. 1.8 cm / 0.71 inch. 2.0 cm / 0.79 inch. Package including 40pcs * Black 3x8mm washer (internal x external diameter). N25pcs black washer 5x10mm (internal x external diameter). N40pcs black washer 6x10.5mm (internal x external diameter). p> N25pcs black washer 8x14mm (internal x external diameter). N20pcs black washer 10x15mm (internal x external diameter). N5pcs black washer 12x18mm (x internal of external diameter). N3pcs Black washer 16x24mm (internal x external diameter). N3pcs Black washer 18x26mm (internal x external diameter). N3pcs Black washer 20x28mm (internal x external diameter). N40pcs white washer dia.3mm N25pcs white washer dia.5mm N40pcs white washer dia. 6mm N25pcs white washer dia.8mm N20pcs white washer dia.10mm N5pcs white washer dia.12mm N2pcs white washer dia.16mm N2pcs white washer dia.18mm N2pcs white washer dia.20mm