An automatic gain controller for controlling gain values of an optical fiber amplifier. A sensor unit detects triggering of a flush water stream through the toilet bowl within the flushing water period t1-t2 at a time ts. The static scheduler is used in conjunction with a hardware description language circuit design, a virtual test bench, and simulation software. The retainer can sustain ample lubricant near the lips. 01 to 2 wt % of a fluoride-containing compound. The product dispenser may further include a vend interface unit to interact with a controller and consumers, whereby the consumer are able to place a demand on the vend interface unit, and await a dispensed filled product receptacle.