Pearl? Parallel and Wedged Oyster cells are ideal sample holders for liquid and viscous samples. They hold samples in the horizonal position, have an injection port to accommodate volatile samples, and can be fitted with either ZnSe or CaF2 windows. The bottom half of a cell determines the cell's path length. There are six path lengths available: 25 μm, 50 μm, 100 μm, 200 μm, 500 μm, and 1000 μm.