Sprinkler waterflow device ranging from 1" pipe to 10" pipe and with or without retard switch. The Model VSR is a vane type waterfl ow switch for use on wet sprinkler systems. It is UL Listed and FM Approved for use on steel pipe; schedules 10 through 40, sizes 2" thru 8" (50 mm thru 200 mm). LPC approved sizes are 2" thru 8" (50 mm thru 200 mm). The VSR may also be used as a sectional waterfl ow detector on large systems. The VSR contains two single pole, double throw, snap action switches and an adjustable, instantly recycling pneumatic retard.