This set of copper washers are made of quality copper material. They have good electrical conductivity and thermal conductivity. Comes in a nice case and are in individual comparments by size. Insert paper has actual sizes so it is visible when case is open corresponding to each compartment making it easy to identify the washer size you need.Specification: - Color: As shown. Material: Copper. Package size: approx. 2 x 2.6 x 1.5 cm. Quantity: 300pcs. Size: M5*9*140pcs M6*10*140pcs M6*12*120pcs M8*12*130pcs M10*14*130pcs M8*14*120pcs M12*16*125pcs M14*18*125pcs M12*18*1.520pcs M16*20*1.520pcs M16*22*1.515pcs M20*26*1.515pcsFeatures:- Top quality copper material. Good electrical conductivity and thermal conductivity. 300Pcs solid copper sump plug washer set. All contained in a compact and see through compartmented plastic case. Great for sump plugs, water, fuel and hydraulic fittings. A sump plug washer set to suit all types of engines like cars, marines, generators, machinery and plant.