The JK (Juliana Korver) Aviar is made from the driver mold in a special blend R-Pro plastic that is more flexible and grippier than the other Aviar models. It has the same flight characteristics as the KC Aviar. Its softer plastic is better in colder climates and for those who have dry hands and require a tackier grip.
This is my Putter, but I think the real strength of this disc shines when it is thrown as a driver. I use this disc for drives and Mid-Range shots between 240 and 150 feet. I will often use it on shorter upshots as well, but feel quite confident with it when throwing it hard. I really like this disc for short sidearm shots as well. Juliana Korver: Five-Time Women’s World Champion