THIS MOBILE WORKBENCH IS CONSTRUCTED WITH 14 GA FULLY ARC-WELDED LEGS THAT ARE JOINED TOGETHER WITH A STRINGER. THIS WORKBENCH HAS 4"" 330# CAPACITY RUBBER OVER STEEL CASTERS THAT ARE WELDED TO THE 5"" ADJUSTABLE LEG CAP. A 12"" LOWER SHELF IS INCLUDED WHICH CAN BE MOUNTED IN (3) AREAS ON THE BOTTOM LEG STRUT. THE 12"" SHELF HELPS TIE THE LEGS TOGETHER AND INCREASE SUPPORT. A FULL DEPTH 24"" BOTTOM SHELF CAN ALWAYS REPLACE THE HALF DEPTH SHELF FOR AN ADDITIONAL COST. THIS PRODUCT IS MADE IN USA.