This is an Indio Mandarinquat grafted onto a Clem-Yuz, which was grafted onto Poncirus trifoliata rootstock much earlier. Odd combination, but the Mandarinquat seems to be thriving (all the growth you see is mandarinquat). I decided I didn’t need another Clem-Yuz, so just grafted top of it. The interstock (Clem-Yuz) is about 3 inches long. It was not an intentional decision to use Clem-Yuz as an interstock. Fortunately most citrus are graft-compatible!