In terms of metrics, 1 SCU comes in at 1.25m3 which is 1m3 of cargo space with 125mm protection on each side and a lid. So thats means a edge has 0.125m+1m+0.125m=1.25m 1.25x1.25x1.25=1,953125m3 and not 1.25m2 When a box has 1.25m3, than each edge has 1.077m, and that means one wall of that box has 38.5mm.