Our horizontal storage rack is a fully welded heavy duty steel framework with five pairs of 350mm long support arms.
Diagram shows 3 bay setup, this only needs two racks. Racking sections are usually placed to give a 550mm gap, this makes the arm spacing consistent.
These units are not designed to be free standing and should be firmly fixed back to the wall and if possible to the floor. please ask for advice if you are unsure about the fixing method for your location.