In clear, translucent red, or translucent blue, these see-through HEI kits offer a more durable alternative to OE parts, as well as a unique finishing touch under the hood. They are made of non-cloudy, high-density materials to meet ASTM 638 tensile strength and UL 94 flame retardant standards. The cap has brass contacts for the best tracking resistance and conductivity, especially when compared to OE aluminum contacts.