The difference between a tik and a mantle is not decorative. In the eastern and North African practice the scroll never leaves its case during the reading. The case is set upright on the reading desk, the hinged halves are swung open, and the two rollers stand vertically with the open columns of text between them. The reader stands to the text rather than leaning over it, the congregation gathers around a standing object, and the scroll is carried through the synagogue as a closed cylinder with its crown or finials on top. In the Ashkenazi practice the mantle is removed, the scroll is laid flat and unrolled horizontally, and the whole gesture of the reading is different.
The practical consequences run in both directions. A rigid case protects a scroll well, keeps it clean, and makes it easy to carry in procession, but it is heavy and it fixes the reading position. A mantle is light and cheap but leaves the parchment exposed. Both arrangements have produced their own craft traditions: silver repousse, brass sheet, inlaid and painted wood, hinges, clasps and dedicatory plaques on one side, and embroidery, breastplates, pointers and finials on the other. In practice many eastern cases carry finials as well, so the two vocabularies overlap at the top of the scroll even where they diverge everywhere else.