Here is my latest headed out the door. This is a Accuphase solid state amp that weights in between 60 and 70 pounds. Total packed weight is 80 pounds. Nothing exceeds like excess, so the 1" styrofoam corner blocks are held in place with 4" of high density foam on all sides. Added some 1" styrofoam to make it all fit tight. The box is 275# double wall.