Holley Water/Methanol Driver Module 554-115 | These Holley water/methanol injection driver modules are designed to driven by an HP EFI or a Dominator EFI ECU. They will drive up to two water or methanol solenoids and are made out of high-quality materials to ensure long-lasting durability and performance. So, if you're in the market for a high-end water/methanol injection driver module, Holly has what you need.