I've heard of coin cells failing due to air freight. The pressure changes are always something to consider. I put a lot of camping gear in ammo cases. You can always tell which cases seal because they are a bugger to open after a trip from the mountains. ------Original Message------ From: J. Forster To: lists@lazygranch.com Cc: Discussion of precise time and frequency measurement ReplyTo: jfor@quik.com Subject: Re: [time-nuts] Large Qty HP C-Beam Tubes available Sent: Jan 15, 2011 10:05 AM Yes. If they are on a plane too long, the time will be off a bit. Einstein predicted that and Bob Pound measured it. :) Look, I suggested ground because virtually anything can be shipped that way, up to and including BW and CW agents and nukes. A spec of Cs is not an issue. -John ================ > Is there an issue with altitude change (air freight) for the tubes. > >