Cheerios is an American brand of breakfast cereals manufactured by General Mills, consisting of pulverized oats in the shape of a torus.
In some countries, including the United Kingdom, Cheerios is marketed by Cereal Partners under the Nestlé brand; in Australia and New Zealand, Cheerios is sold as an Uncle Tobys product.
It was first manufactured in 1941 and was originally called CheeriOats but the name was changed to Cheerios in 1945
As well as plain cheerios, there are many other different variations of cheerios. (source)
So can hamsters eat plain cheerios?
Yes they can eat them, they are fine for them to eat as long as they are just plain.