Nylon 6/6, standard round tapped spacers with 3/16" to 1/2" OD. Spacers are listed by the inside diameter and thread pitch, the outside diameter and by the length. Fasteners are precision molded or machined of Nylon 6/6 - a highly crystalline, light-weight, high melting thermoplastic resin. The mechanical advantages include toughness; good thermal properties; abraision, friction, and chemical resistance. Parts are natural but can be dyed black or various colors on request! Specify color at Checkout. Max. tensile strength: 12,000 PSI., resistance to heat: 270-300 deg F.