Abstract: An apparatus includes a crossbar to which a plurality of accessories using different mechanical interfaces may be attached and detached. The crossbar is instrumented and provides information, such as a weight change due to addition to, or removal of, items from an accessory on the crossbar. An extensible bracket attaches the crossbar to a supporting structure, decreasing mechanical strain on the crossbar due to minor misalignment of the supporting structure. Accessories such as wire hooks, shelves, bins, and so forth may be supported by the crossbar. A tether device, locking cam device, or clip device may be used to prevent lateral movement of components such as the accessories or the entire crossbar relative to its supporting structure. A baffle may be affixed to the crossbar to constrain airflow for operation in a temperature-controlled case.