Designed for aerial devices, digger derricks, ncrete pumpers, and cranes with outrigger feet up to 24″x24″. The setup of a SafetyTech Base Pad and two ProStack Blocks has a 110, 000 lb. worit load limit and a max allowable pressure of 500 psi. Under 55 lbs. per block; Each block adds 6.0″ of stacit height; Pyramid interlocit system