Four Brand New Solid 24" Galvanized These are Four Brand New Solid 24" Galvanized Swivel Screw Jack with Base Plate . 18" adjustable Thread, 1 3/8" OD will fit on 1.69" and 1.625" OD Scaffolding . 18" adjustable Thread, will fit on 1.69" and 1.625" OD Scaffolding frames. The Adjustable Thread will help you set your scaffold frames level. IF YOU HAVE ANY QUESTIONS PLEASE CLICK ON (CBM1290) then RETURNS.