Protect-A-Boot Sleeves are superior Protection for Extreme Angled Plug Wire BootsDEI Protect-A-Boot Sleeves are uniquely designed to protect spark plug boots & wires against the harmful effects of direct and continuous heat - up to 1200°F. Continued exposure to extreme heat geneated from the engine block, exhaust manifold and headers can cause burn through, hardening or cracking of the spark plug wires and boots.Like the original Protect-A-Boots product, the sleeves offer the same heat protection and double wall construction for added strength and durability, yet are designed to provide a universal fit for extreme angled, oversized, or rigid boots like ceramic ignition wire ends. The 1-1/4" I.D. at both ends and pliable construction allow the sleeves to fit multiple angled spark plug boots.Otherwise the material is the same as DEI's popular Protect-A-Boots that are made from a tightly woven high temperature resistant glass fiber material.