Model DS25 Flowmeter works on variable area principal, utilizing float guided in cylindrical measuring tube by means of slotted nozzle. Externally mounted pointer indicator, magnetically coupled to float indicates flow rate against calibrated or arbitrary scale. Indicator assembly also houses optional alarm outputs, analog output, and totalizer. Available pipe sizes range from 1/2 to 6 in., with FS ranges from 0.01 to 440 gpm water and 0.44 to 1,100 scfm air.