4 feet 5 inch To 7 feet 9 inch , 15 Gauge Adjustable Jack Post, Max Ext Load 11,350 Pound S, Min Ext Load 18,000 Pound S, Additional Support For Crawl Spaces, Attic, Staircase Or Decks, Adjusts With .75 inch Wrench, O.D. Gauge and Tube Dim 2.25 inch x 15 Gauge x 45.5 inch , Screw Size 1 inch x 7 inch , -5 Thread Support, Collar Size 2.25 inch x .5 inch , Support Pins .5 inch x 3 inch , 13 Gauge Plate Size 4 inch x 5 inch , Corrosion Resistant Inside and Out, Double Carriage Bolt and Nut Zinc Coated For Added Safety, Heavy Plates Suited For Wood And Steel, Deep Dish Self-Centering Plates.