Norco Professional Lifting Equipment - The 81004C Heavy Duty 3 Ton Capacity Jack Stands (Set of 2) are for automotive use where vehicle is to be supported before making repairs. It features a unique spring loaded pawl that provides constant locking pressure against lifting column, a four legged base with foot pads for added strength and a more secure footing on asphalt, and common machine bolt that secures lifting column to stand and provides added strength when stand is continuously lifted and handled by the column.