About This ✅This set of Step Jaws is Dedicated for VINWOX 3.75" SCK4-3.75 & 4" SCR4-4 4-Jaw Self-Centering Wood Lathe Chuck, Same Jaw Fixing System Across PSI “C” Series and Craft Supplies 3.75” Apprentice Chuck – TOTAL INTERCHANGEABILITY! (Won't Fit to Nova, Record Power, Vicmark & Oneway Chucks) MAKE SURE TO CHECK YOUR LATHE CHUCK FIT FIRST to Avoid Unfitting or Return. ✅Ideal Gripping in the Expansion Mode for Vases, Cups, etc ✅2 Step Sizes for Optimum Gripping of Bases with Minimal Damage to Wood Projects Plus Internal Spigot Grip ✅Internal Spigot Grip for Small Unsupported or Supported Spindle Work ✅Step Jaw Specification: Narrow Step - Outer Diameter 0.6"; Wide Step - Outer Diameter 1.4", Exterior Workpiece Grip Range 3/32" To 1-7/8", Interior Workpiece Grip Range 11/16" To 3-3/8", Weight 0.75 LB (0.34 Kg), with 8 Mounting Screws Overview Brand : VINWOX Material : Chromium Vanadium Steel Item Diameter : 1.4 Inches Item Weight : 0.39 Kilograms Compatible Devices : Lathe