Vintage hydrant flow gauge.
Fullsize image: https://s3-us-west-1.amazonaws.com/h...e_fullsize.jpg
https://s3-us-west-1.amazonaws.com/h...flow_gauge.jpg
Previously:
https://www.homemadetools.net/forum/...281#post146162
https://www.homemadetools.net/forum/...422#post154672
https://www.homemadetools.net/forum/...792#post152292
https://www.homemadetools.net/forum/...890#post100252
https://www.homemadetools.net/forum/...640#post147608