Jack Screw Set, Height (In.) 6-3/8, Dia. (In.) 1-1/4, Application Leveling Work And General Tool Room Use, Includes 6 Pieces: 20-Pitch Jack Screw 2-1/4 to 3-3/8 in Range, Extension Base 1 in and 2 in , Auxiliary Pointed Screw, Extension Base for Non-Flat Surface, Extension V Base for Cylindrical Forms