As I understand the USPS website, flat rate envelopes (regular or padded) go to $16.95 to international destinations - a considerable jump. Domestic flat rates go to $5.15 for FR Envelope, $5.30 for Padded FR Envelope and $5.35 for small FR Box. Delivery Confirmation will be 75 cents - a 5 cent increase.

For those of us who only get 5-10 keys in the RR, the cost may be a factor for an international RR - in addition to the length of time the RR takes to travel back and force across the waters. I mail numerous packages to collectors in Europe and have never had a problem with one getting lost - however, I had one that took 25 days to get to its destination because Customs felt it necessary to check it out.

Just some food for thought.