Adjustable Floor JackAdjustable, easy-to-assemble, easy-to-install floor jacks are designed for use 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.No. C-2: 2´10 IN to 4´7 IN compression strength: 14,000 lb. at maximum extensionNo. C-3: 1´7 IN to 3´0 IN compression strength: 16,000 at maximum extensionNo. C-4: 1´0 IN to 1´3 IN compression strength: 18,000 lb. at maximum extensionNo. C-79: 4´6 IN to 7´9 IN compression strength: 11,350 lb. at maximum extensionNo. C-84: 4´8 IN to 8´4 IN compression strength: 9,100 lb. at maximum extensionNo. Big Moe: 4´8 IN to 8´4 IN compression strength: 38,000 lb. at minimum extension, 20,000 lbs. at maximum extensionView Akron Products website for details and **information on this product.