I assembled the Shuntong Atlas shelving unit in about 2 hours - including breaks, inventorying, and final testing. The pieces are exactly cut, and fit perfectly. They have a short video which actually helps. The unit currently hosts about 700lbs, with room to spare. I only needed 3 shelves, so the 4th stores neatly beneath the rack on the floor. To keep the L-angle legs from permanently indenting the vinyl floor we put 4 sliders under them. For safety, the sharp top of the legs (if a shelf is not needed at the top) should be covered with plastic covers, which we've ordered.