Sentinel GPS BRT-1aHR WM Basic Wall Mount High Range Recycle Timer The BRT-1aHR Basic Recycle Timer - High Range is designed to control equipment that has to be turned On and Off at precise, repeated intervals Hydroponics, drip irrigation, aeroponics, CO2 injection - these are just many of the tasks the BRT-1a can control The BRT-1a features a readily visible switch to alternate between day or night or continuous operation making it easy for the end user to differentiate which mode it is operating in