Do It Pinch-On Sinker Size 3/4, 1, 1 1/4, 1 1/2 Oz. Do it Mold 3313 Cavities 4 Total Do it Mold (3313) Pinch-On Sinkers are very easy to attach and remove from the line. The ears of the sinker are simply folded over the line, which gives the Pinch-On a streamlined shape when attached. It is important to use only soft lead when casting Pinch-On Sinkers to ensure that the ears will bend easily.