There is one screw missing from the manhole or one nut and bolt. I do not know what this was used for, but it may have been a vent on the sidewalk for underground tunnels. I have not weighed it, but it is very heavy. It has an overall thickness of approximately 1 in and the grating itself is approximately three-quarters of an inch thick. The round part of the Great is approximately 1 5/8 in thick.
The item "Large Vintage Cast Iron Sidewalk Grate Vent With Manhole Like Insert Heavy" is in sale since Friday, June 7, 2019. This item is in the category "Collectibles\Metalware\Cast Iron". The seller is "captnshooks" and is located in Ashland, Wisconsin.
This item can't be shipped, the buyer must pick up the item.