TEAR DROP SNAP-IN LOCKING SLOTS ENSURE A SECURE AND STABLE UNIT. ONE PIECE BOX-FORMED REINFORCED UPRIGHT FRAME PUNCHED 2"" ON CENTERS FOR MAXIMUM ADJUSTABILITY. 3 1/4"" X 4 1/4"" X 12-GAUGE BASE PLATE ANCHORS UPRIGHT TO FLOOR AND DISTRIBUTES WEIGHT EVENLY. WELDED BRACES PROVIDE MAXIMUM RIGIDITY AND STABILITY. UPRIGHT FRAME STARTER UNIT REQUIRES TWO FRAMES ADD-ONS REQUIRE ONE FRAME. FRAME CAPACITY SHOWN IS BASED ON 36"" BEAM SHELF SPACING.