This handy pen maker's tool has 7 useful functions. Pen blank center Finder - cross hair center Finder for square blanks and Bullseye center Finder for Non square blanks. Pen tube length measurer - measures tube length in inches and millimeters. Inch to cm conversion - instantly convert from inches to cm by aligning a straight edge across the tool. Pen tube sizer – slip your tube through and the go/No go gauge will identify your tube odd. Drill bit sizer – slip your bit through to identify the diameter of your drill bit. Square – ideal for squaring the drill bit on a drill Press for blank drilling. Chisel angle Finder – measures a chisel’s angle for accurately grinding your chisel.