They are very thick and sturdy and are made from black anodize 440 stainless steel. Because of the thickness and heaviness of these stars, it helps with the balancing and airflow when throwing them and allows its throwers to have a sure stick. The length of the blade measures 1 inch. Also, the ninja star has Chinese engravings on it for a more authentic looks and feel. The package includes one black Ninja Throwing star with a black nylon carrying sheath with belt loop. Be careful with these stars because it is very sharp. Overall Diameter: 4 inch