Na Nach is the name of a subgroup of BresloverHasidim that follows the teachings of Rabbi Nachman of Breslov according to the tradition of Rabbi Yisroel Ber Odesser (called the Saba, or grandfather, by Na Nachs). The Saba is believed to have received an inspirational note, called the Petek (note), from the long-deceased Rebbe Nachman. Devotees of the group, colloquially called Na Nachs, make themselves quite visible in the streets of Tel Aviv, Jerusalem, Safed, Tiberias, and other Israeli cities as they dance atop and around moving vans to techno-Hasidic musical compositions, with the goal of spreading joy to passersby. They distribute their literature from sidewalk tables on the downtown streets and near bus stations, often accompanied by blaring music. They are identifiable by their large, white, crocheted yarmulkes bearing the name and song from the petek that Rabbi Odesser revealed: Na Nach Nachma Nachman Meuman. Besides publicizing this phrase on billboards and bumper stickers, Na Nachs and their admirers have made it a common graffito throughout Israel.
^Preston, Benjamin (15 June 2011). "New Hasidic Radicals Bellow Down Tel Aviv's Streets". The Forward. Retrieved 17 June 2011. It’s a scene increasingly common in Tel Aviv, Jerusalem and other Israeli cities where the loud, brightly painted Ford cargo vans associated with Israel’s hottest new Hasidic sect have become a recognizable sight.