“Duties” explained. 

No matter the item’s physical size, its wall thickness (and therefore its weight!) will increase as we progress up the scale of Light – Medium – Heavy – Extra Heavy – and, Severe Heavy Duties. 

The main issue to remember is that a specific duty, say Heavy Duty, is a different wall thickness on smaller items than on larger items. The wall thicknesses on every item and every duty are published to ease your decision.