Micronet/Fantom Drives has multiple storage products. Some list the rotational velocity as part of the specification, and some do not. We do so in order to qualify a broader selection of disk mechanisms at the best possible costs, while offering more specific requirement products to offer customers storage solutions more tailored to their needs. The rotational velocity is an aspect of the storage product's overall performance, and may be required for specific professional applications such as pro audio capture- consult your application vendor's system requirements for more information.