A New Solution for the GM Quad 4 Coil-on-Plug Boot Problem The GM Quad 4 boot has enjoyed exceptional aftermarket sales for a very long time due to a large vehicle population and high failure rates. The OE boot is attached to coil pack and uses a plastic housing and plastic clip. Typical premature failure due to this design is deterioration of the housing and clips leading to cracking, burning and dielectric failure. SMP recognized the market demand for a better solution. Our wire & cable business unit engineered a heavy duty durable solution. Our solution... a patented one-piece molded design. Engineering a 100% high grade silicone insulator, this unique design eliminates the need for the OE plastic housing and clips, which have a great tendency to wear out and fail in the high heat, underhood environment. The SMP boot lasts longer, performs better and virtually never fails due to cracking clips or housing like the OE boot it replaces. Another engineering victory for SMP.