Product Description MIG welded and riveted construction. Will work on either inside or outside ladder face. Will accommodate up to 18" wide-plank. Adjustable to fit round or D-Rung ladders. Complies with OSHA requirements. From the Manufacturer 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. Qual-craft now offers 2 new accessories for the ladder jack scaffolding. The new accessories are a Ladder Jack Safety Rail holder and Safety Rail to complete the Ladder Jack Scaffolding System.