Punched, or perforated, square tube is a hollow tube made of steel with holes punched in regular intervals. The zinc coating offers rust protection so the tube can be used indoors or outdoors. Punched tube can be telescoped inside other sizes to add adjustable height put the 1 in. Dia. tube inside the 1-1/4 in. Dia. tube which can then go inside of the 1-1/2 in. tube. This allows the height to go from 36 in. up to 72 in. or more if you telescope all 3 Dia. offered. Use a bolt and nut to lock in the desired height and make sure that the holes are lined up so the bolt goes through the nested tubes.
