These are 6" JOTI make FRP diaphragm valves for corrosive atmospheres. They are in use in sugar factories satisfactorily. Based on type chemicals prices may very accordingly. Being FRP they are easy to use and maintenance free. We also supply 8"/10" JOTI make FRP diaphragm valves. You are also getting benifitted of our experience of 30+ years in these specialised materials.