If you are searching for a Jumbo Pistachio Producer, you need to know that Iran calls in Kalleghouchi Pistachios growing in Khorasan and Rafsanjan.
Jumbo pistachio is available in following sizes after sorting:
20-22, 22-24 and 24-26
These above mentioned sizes are the most common ones. In fact, there are some other sizes that can not find normally.