Key (1) Indicates cells are temperature compensated (2) Cells with BNC connection; not temperature compensated (3) Cells with banana plugs that require an adapter (inquire) (4) Cells with 7-pin DIN that require an adapter (inquire) (5) Replacement flow cells available (013017, 013017A) (6) Cell requires cable (010015) for use with models 555A, 550A, 162A, 130 & 135 series