Watch out shipping 4.1 boards in regular letter envelopes. They apparently no longer meet the "minumum bend radius" to go through the USPS sorting machines so they often will get shredded. Of 5 I've sent out, 4 never made it compared to a 100% success rate on 4.0 boards. I started sending them in padded envelopes, which unfortunately means they cost $2.20 to mail.