Plast-O-Matic Series GY Double Cylinder Wall Flow Indicators 1/2″ – 3″
Plast-O-Matic Series GY Double Cylinder Wall Flow Indicators 1/2" - 3"
https://www.watercareproducts.com.sg/product/sight-glasses-level-indicators-calibration-columns/plast-o-matic-series-gx-gy-gyw-sight-flow-glasses