BL9-3 is dedicated to biological x-ray absorption spectroscopy. Three main types of experiments can be performed: XAS of very dilute (sub-millimolar) solutions of metalloproteins, polarized single crystal XAS studies. It is equipped with a 100-element Ge detector array and a LHe cryostat when used for solution XAS studies. A combined XAS/crystallography instrument focusing on single crystal XAS, is based on a kappa goniometer, a MAR165 CCD camera or MAR145 IP detector, a LHe cryostream sample cooler and specialized software.