The Qual-craft 2 rung, short body aluminum ladder jack is MIG welded and riveted construction for strength and durability. This high quality aluminum ladder jack will work on either the inside or the outside of the ladders face, and will accommodate up to an 18 inch wide plank, and is adjustable to fit round or D rung ladders. The ladder jack system is sold in pairs. The capacity is 2 workers, pending duty rating of ladders being used plus 75lbs. between 2 ladders.