eTool : Scaffolding - Supported Scaffolds - Ladder Jack | Occupational Safety and Health Administration
Plank Fall Protection Safety Systems - WorkSafe Company
MetalTech 21.75 in. x 10 in. x 16.75 in. Aluminum Adjustable 2-Rung Ladder Jacks for Scaffold Extension Boards, Ladder, or Plank E-LJ20P - The Home Depot
Ladder Jack - Ladder Accessories - Ladders - The Home Depot
Qual Craft 2420 2-Rung Aluminum Ladder Jack - Walmart.com