https://www.reinders.com/rain-bird-6-station-expansion-module-for-esp-me-controller/
Rain Bird - 6 Station Expansion Mod For Espme Controller
Add up to 6 additional stations to the ESP-Me or ESP-SMT3 Series Controller. Hot swappable unit allows for quick expansion available from Reinders.com.
rain birdstationexpansionmodcontroller