Cell Holder Shimzadzu universal, rectangular, four-cell type. Holds four rectangular cells with an optical path length of 10, 20, 30, 50, 70, or 100 mm. Note: Requires the Four-Cell Sample Compartment unit (P/N 206-23670-91). When a rectangular, long-path cell is used on the reference side, its holder (P/N 204-28720) is also required.