Control pool or spa functions and costs E-Command 4 is the easy and cost-effective way to automate essential pool or spa functions. Control filter, pump and lighting. Automate schedules to turn lights on at night or manage energy saving 2-speed pumps for better efficiency. Functions can be set up to run automatically or can be controlled from an optional wireless remote. The base system supports 3 high-voltage relays, 1 valve, 1 heater and solar but 2 optional relays can be added. What ever the function, pool owners can maintain basic control of their pool or spa with E-Command.