h2flow FVJ-R 2" - 2.5" Jandy Valve Flowvis Retrofit Kit is an ingenious in concept and flawless in operation, FlowVis® has been revolutionizing the way flow is measured in a myriad of applications and environments since its inception in 2012. With unrivaled average accuracy, greater installation flexibility, and more NSF 50 certified models than any other brand, it’s easy to see why FlowVis® is a brand of flow meter you can put your trust in.