Zipper Dies 1 3/8" DiameterZipper Dies Full Die Set Zipper Bridge The Zipper Bridge knits the clay back together, eliminating seam failure and cracking during drying & firing. It also allows for immediate manipulation of your extrusion into other forms. Precision Radius Extrusion Dies Very strong and smooth extrusion allows the clay to flow through the die into compression & flow out so you can work directly out of the extruder without sharp edges that could make your extrusion