The Thirikwa Cooperative Society is located on the Upper Medium (or UM2) zone of Mt. Kenya. The wet mill Gakuyu-ini is about 130 kilometers from Nairobi City.
The AA, AB and other grades used to classify lots in Kenya are an indication of screen size only. They are not any indication of cup quality. The AA grade in Kenya is equivalent to screen size 17 or 18 (17/64 or 18/64 of an inch) used at other origins. AA grades often command higher prices at auction though this grade is no indication of cup quality and an AB lot from a better farm may cup better.