4 Scaffold Screw Jack Galvanized 24" X 1-3/8" with A Large Wing Nut for Adjust Scaffolding Frames 4 Scaffolding Screw Jack Galvanized 24" X 1-3/8" with A Large Wing Nut for 18" Adjustment Scaffolding Screw Jacks are used anytime Scaffolding is built on ground that is not level the 24" Scaffolding Jack, you get 18" of adjust-ability. For fine adjustment of rolling and stationary scaffolding. The Screw Jack is made from a 1 3/8 inch Solid Stem with 6" x 6" base & a large wing nut 4 adjustment IF YOU HAVE ANY QUESTIONS PLEASE CLICK ON (CBM1290) AND CALL US.