This is the Taytools 300003 Router Bit Template Guide Base Plate Centering Tool for 1/4" and 1/2" Collets HSS, physically acquired through Amazon.com. This router bit centering pin has multiple uses in the woodshop. It can be used to center template guides to router base plates, align router base plates in both hand-held and router tables, set up router bits for slots or dados and check router collets for run out. Fits both 1/4 inch and 1/2 inch router collets. Precision machined from high speed steel. 3 inch overall length.