Suitable for use as targets in laser tracking systems, ball-mounted hollow retroreflectors from PLX Inc. have apexes that are aligned to the absolute center of the stainless steel ball within 0.0001 in. for enhanced accuracy. The mirror coating is overprotected silver. The devices allow the tracking system to provide a wider angle of acceptance. They are available with 1 1/2-, 7/8- and 1/2-in. diameters. The company says that the devices work with all major laser manufacturers' systems.