Cork borers for solid corks and rubber stoppers. Each is a set of (3) 3-3/4" long brass tubes with sharpened ends and red-plastic T-handles. Three diameters that are 9/32" and 7/32" and 5/32". They're nested on the 4-3/4" pin used to clear the plug from the tube.
Keep the tool well lubricated while boring. Hand or dish soap works well. If you start to feel the friction increase- remove the toll and add more soap to the bore. Be sure to place against a wood or plastic cutting board while boring. Cleaner straighter holes come with patience.