These special 25mm extended jaws act like a pin chuck by expanding into a pre-bored hole. This is a useful jaw when turning free form edge bowls. The jaw will lock into a simple bored hole; the advantage over a standard pin chuck is that you don't have to bore to an exact size. Simply expanding the jaw means turning can commence without further delay. The longer stand-out of the jaws allows for a very powerful spigot grip for smaller work such as lace bobbins and delicate pots etc. The jaws also have a dovetail to mount small bowls (up to 150mm diameter). The jaw expands into a recess between 26mm and 46mm diameter. When gripping a spigot the range is 10mm to 31mm diameter. These jaws will also hold square stock between 7mm and 38mm. Suits both SuperNova2 and Nova G3 chucks.