Mighty-Seal® Raintight Steel Reducing Washer 3/4″ to 1/2″
https://hotfix.nsiindustries.com/product/mighty-seal-raintight-steel-reducing-washer-3-4-to-1-2/
The Bridgeport 3/4″ to 1/2″ Raintight Galvanized Steel Reducing Washer is used in pairs to reduce the size of knockout holes in a box or enclosure in wet locations. Users can maintain NEMA 2, 3, 3R and 4 rating on listed enclosures.