Air and Water Flow Meters by Dwyer® Instruments are used to indicate or manually control air or gas (pneumatic) flow from 0.2 SCFH TO 100 SCFM, and water (liquid) flow from 0.5 GPH to 20 GPM. The precision-machined clear acrylic bodies provide excellent visibility and are practically unbreakable. Direct reading scales are hot pressed into the plastic and will not wear off. Brass metering valves (2" and 4" models) contain valve stems, which are easily removed for inspection and maintenance. Two metal mounting inserts on the back of the bodies provide for easy panel mounting. All models are back ported.