This bottle stopper mandrel has small threads that fit the following stoppers: - Cork & Chrome Wine Bottle Stopper - Tear Drop Wine Bottle Stopper with Standard Stud - Black Titanium Presentation Bottle Stopper - Titanium Gold Presentation Bottle Stopper - Stainless Steel Wine Bottle Stopper The threads are 1/4-20 and uses a 6mm drill bit. Hold the mandrel in a drill chuck.