He has the highest grade of koa wood available. 218939879 bucks an ounce lol. his uke also has a nice gloss finish. Either, Rosewood or Ebony Fretboard(inlay abalone shell of his initials: JS). Im not sure what type of neck he has, but im assuming its koa. He also usuallly has a slotted headstock with top quality tuners. He uses D'addario strings that he pretty much invented for the uke. The uke costs about 6,500$ I think.
So I think that covers most of it.
...yes I am obsessed with jakes ukulele. It's just so perfect lol.