Looking for information on Christmas crackers

On BA's website:

Party poppers and sparklers
Christmas crackers
Crackers may be carried in your checked baggage on flights out of the UK providing they meet the following restrictions:

The crackers must be commercially manufactured (homemade crackers are not permitted).
Maximum two boxes per passenger in the manufacturer's original packaging.
The crackers must be for personal use only.
Crackers are not permitted in any bags out of the US; rules may vary in other countries.