Adjustable, easy-to-assemble, easy-to-install floor jacks are designed for temporary support during remodeling projects to reinforce stairs, porches, decks, or weak floors. Constructed of premium quality steel and coated to prevent corrosion. All moving parts fit snugly to avoid lateral displacement and the top and bottom plates are deeply embossed to mitigate movement and prevent dishing. The heavy-duty high-carbon steel is double locked for added safety. Compression strength is defined as testing to the point of failure. To determine safe or allowable load consult a licensed engineer.