A control for use in a hydraulic circuit where the control can act as a valve and an auxiliary pressure source for the hydraulic circuit. The microcavity includes a first mirror, a second mirror, and a layer of an active material. Thaxtomin A and structurally similar compounds can be used as natural herbicides to control the germination and growth of weeds in cereal, turf grass, Timothy grass and pasture grass cultures with no phytotoxicity to these crops. In one embodiment of the present invention, at an administrator level, a handler object 611 in turn accesses accessor object 511. A stop pin, stored in the handle when not in use, is provided to set the container at intermediate heights on the guide member.