Walker Products 900-P2066 Thunder Core Ultra Coil Boot is engineered to meet or exceed Original Equipment Manufacturer (OEM) quality. It is precision made for outstanding performance and manufactured to meet or exceed all original equipment specifications and test requirements. Replacing defective Coil on Plug Boots with a Walker Thunder Core-Ultra Coil on Plug Boot set will increase fuel economy, improve engine performance, and produce lower emissions. Walker Products is an ISO 9001-2008 / TS16949 certified company that specializes in the manufacturing and distribution of Fuel System Components and Automotive Engine Management products. Walker is committed to meeting or exceeding the Original Equipment Manufacturer (OEM) or equivalent standards and specifications. This effort is backed by Walkers own manufacturing, product management and engineering expertise.