Ocean Optics Inc. uses a proprietary process to manufacture its XSR Xtreme solarization-resistant optical fiber assemblies for deep-UV (<300 nm) spectroscopy applications. The fiber transmits signals down to 180 nm and is highly resistant to UV degradation. The assemblies are available in core diameters of 235 and 455 μm and in standard lengths of 25 cm and 1 and 2 m, with custom lengths also offered. They have an aluminum coating, stainless-steel BX jacketing and high-quality SMA 905 connectors for coupling to the company’s spectrometers and accessories. A 6-around-1 reflection probe version is available for reflection and fluorescence from solid surfaces, or for backscattering and fluorescence in liquids and powders.