Time gentlemen, please.

The Irish Times regularly advertises “reader offers” and today they offer us an outdoor clock which digitally displays time, date and temperature.

The ad makes the following claim for the device: “This amazing clock is accurate to less than a second in a million years”, which prompts a couple of questions:

(1) How have the manufacturers validated this claim?

(2) How would I go about claiming a refund in, say, 500,000 years should the claim prove to be invalid?

I've directed the query to "Madam".