I recently shipped the Dynaco 400 I had listed here. I bought heavy duty boxes at U-haul and lined all sides and top & bottom with 1/2" drywall left over from a project. Then I cut 1" foam insulation for the bottom and securred the amp in the box with more panels of foam until the amp was snug all the way around the box. I tracked it until it arrived. Never heard back from the buyer and can only assume it arrived ok.