The Chex cereal pieces in official store-bought Chex Mix are not the same as the pieces you get in cereal boxes!

Just take a look at the photo above. The Wheat Chex on the left is from a bag of Chex Mix. The Wheat Chex on the right is from a cereal box.

Notice how the cereal box one is flatter, denser, has little rectangular holes instead of little square ones.

The taste and texture of the Chex are different too. The one from the Chex Mix tastes better and has a more pleasant crunch.

One may be optimized for delicious dry snackiness while the other is optimized for being eaten in milk.

It's interesting to know we can't replicate store-bought Chex Mix at home because the Chex we can buy make for an inferior snack!