4'8" To 8' 4", 11 Gauge Adjustable Jack Post , Max Ext Load 20,000 LB, Min Ext Load 38,000 LBS, Additional Support For Crawl Spaces, Attic, Staircase Or Decks, Adjusts With 3/4" Wrench O.D. Gauge & Tube Dim 2-1/4" x 11 Gauge x 49", Screw Size 11/4" x 7", -5 Thread Support, Collar Size 2-1/2" x 5/8" Support, Corrosion Resistant Inside & Out, Double Carriage Bolt & Nut, Zinc Coated, For Added Safety, Heavy Plates Suited For Wood & Steel, Deep Dish Self-Centering Plates.