The 13950 Shielded Cuvette Holder holds standard 10 x 10 mm cuvettes atop an optical rod. It has an 8 mm wide by 29 mm high rectangular aperture on all four sides. When viewing or detecting fluorescence or other signal through the sides of the cell, the apertures minimize reflected or scattered light from the cell input and output faces. The 13950 includes a 3-inch standard Newport rod.