bass part in even flow

bassist305pj

hey guys im wondering how jeff does that noise, almost like a siren increasing in pitch just after the intro to even flow, you know the bit, before the first verse. i saw on live at the garden he is just sliding up the G string but surely there is more to it than that. also, what strings does he use for his fretless flatwounds or roundwounds? surely someone must have a gear list that tells me.