Manually-operated diaphragm valves for chemicals have wetted components made from materials suitable for compatible chemicals and media. Always refer to the manufacturer's Chemical Compatibility guide for information. Manual-operated valves open and close by hand via a handle, lever, or knob. Diaphragm valves control the flow of chemically compatible media in a system with an elastomer diaphragm that moves into or out of the media's flow path. These valves have isolated stems that do not make direct contact with flowing media and are suitable for applications moving gases, liquids, and suspended solids such as slurries.