I use Alu extrusion that is used on commercial windows, got it twenty years ago, but they may still use it. Bert In a message dated 1/9/2011 3:09:19 P.M. Eastern Standard Time, mspencer12345@yahoo.ca writes: My experiences placing my thunderbolt board in various insulated containers show little or no improvement over simply putting a cardboard box over it to keep drafts away. As time allows I'm going to re run some of the tests using my 5370 and an external standard vs relying on the data from the thunderbolt itself but I'm not expecting to see any significant changes. I've also started to run some tests with disciplining turned off on the thunderbolt and the drift of the ocxo is quite apparent. I'll likely get a heavy die cast box for my thunderbolt at some point.