As a practicing mechanical engineer, I am very impressed at this heavy-duty precision-made bed frame. Everything fits like a glove. I like their decision to USe the same size fastener (with different lengths) and provide the Allen wrench for it. You need no more tools. The assembly instruction is perfect and clear. I am also very impressed at how they attached the purlin beams without tools. Outstanding engineering and manufacturing achievements. They even provide extra fasteners in case some get lost or damaged.