In a large bowl, combine 3 cups Chex rice or corn cereal, 2 cups plain Cheerios, and 2 cups pretzels.
Melt 10 ounces white chocolate wafers. Microwave for 1 minute. Stir and then melt in 30 second increments (stirring in between). Do not overcook or it will burn.
Next pour the melted chocolate over the chex mix and stir until well coated.
Then pour the chex onto a piece of wax or parchment paper and allow to set until hardened (at least 15 minutes).
Store in a zip top bag or covered container. Store on the counter for 3 days or in the freezer for 3 months.