Rain Bird - ESPSM6 6-Station Expansion Module for the ESP4ME Irrigation Controller Adds 6 additional stations/zones to your existing Rain Bird residential modular controllers (sold separately) This 6 station expansion module swaps quickly and can be installed without turning off the controller Only works with Rain Bird ESP Me and ESP SMTe series irrigation sprinkler system controllers Does NOT work with older style ESP Modular or ESP SMT series controllers Can be installed in any open controller slot quickly and easily