Didn't know that. .. .. .... Also, I learned recently:

(1) you can mail a chip in a letter to a foreign country, pay first class international letter postage (with your own stamps on it) and track it for free with the customs number! ... ... ... I tape the chip inside some nice strong cardboard (like from a cereal box), and tape that to paper inside a sturdy envelope. So the whole thing is no more than 1/4" thick and one ounce. Then I hand-address the envelope, put on postage stamps (including $0.21 for non-machinable surcharge), and affix the CN 22 customs form, which is available at all post offices. The customs number on the form can be used to track it all the way to the destination! Track it here:
https://www.usps.com/
Doing this, and weighing no more than 1 ounce, the total postage cost is $1.15 + $0.21 = $1.36 with free tracking (customs number). (Note: I do this using First Class International LETTER rate (not parcel rate). International First Class PARCEL rates begin at about $10, even for one-ounce parcels. First Class International LETTERS postage is about only $1 to $3.)

(2) I was also surprised to find that I could put a foreign country's custom number into the US Post Office's tracking box and track it just as though it was going from American city to American city.
https://www.usps.com/

Robt.
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