The best quality ring designs require perfect wax blanks. The Matt reamer creates smooth parallel walls on your patterns, and then bores straight through the blanks to precise finger sizes. You can also create bezels for round stones or coin holders. The Matt Reamer consists of a precision ground 5/8" diameter steel rod with a large plastic turning knob, a carbide wing blade for facing off side walls, and a carbide boring bit calibrated in ring sizes. It takes only a few minutes to attain proficiency in the use of this ingenious tool. Made in USA.