Review on Efficient Doweling Centering Woodworking Accessories for Precise Transfers by Sean Maples

These are metric center taper plugs although it is clearly stated that they will fit standard sizes. For a triple check, I measured with calipers, drilled holes for 3/8" dowels, and attempted to install them. They didn't fit. Went to hardware store. Bought some and they fit perfectly and measured correctly.