Manufactured of the same material as Heat Sheath, the Plug Wire Sheath was designed as an inexpensive protection for plug wire boots or any spot on a plug wire that is close to heat and requires additional protection. The Aluminized Plug Wire Sheaths can also be used on lines, wires and hoses that need protection in a specific area. The Aluminized Plug Wire Sheaths are 6" long and 3/4" in diameter. • Inexpensive Protection for spark plug boots • Reflects radiant heat from headers and engine • Easy to install • Four per pack