Finally...an economical modular flow indicator you can match to your specific requirements. Easy to see, visual indicator of liquid flow. If one of the "float balls" is lower than the others, there is a blockage. Individual columns clip together so you can gang as many or as few columns as you need. Exclusive O-ring seal and joint clip system is easy to assemble and service. Can monitor up to three spray tips per column. Range of "float balls" lets you match to your flow rate. 3/8" & 3/4" inlet and/or outlet fittings. 100 PSI maximum operating pressure. UV protected material stays clear.