A diaphragm—or pressure—switch works by activating a sensitive micro-switch when material reaches the level of the switch in the bin. It sends an alert that can be used to start or stop a process or alert to a high, medium, or low-level in the vessel. Commonly used in grain, feed, seed or other free-flowing granular material, BinMaster diaphragm switches are offered for either internal or external mounting. They are wired to a light, horn, alarm, or BinMaster point level alarm panel to indicate an alert status.