Outstanding in its field
You're looking at things that some people don't believe really exist.
They're cow magnets.
Each is 1/2” diameter and 3” long
These things are used by dairy farmers and veterinarians to help prevent Hardware Disease.
And no, Hardware Disease is not something your PC picks up from the web.
While grazing, cows eat everything from grass and dirt to nails, staples and bits of bailing wire (referred to as tramp iron). Tramp iron tends to lodge in the honeycombed walls of the reticulum, threatening the surrounding vital organs and causing irritation and inflammation, known as Hardware Disease.
The cow loses her appetite and decreases milk output or her ability to gain weight. Cow magnets help prevent this disease by attracting stray metal from the folds and crevices of the rumen and reticulum.
One magnet reportedly works for the life of the cow.
No word on how you convince a cow to swallow this thing.