Parity 3.5 from Bit9 is a host-based intrusion prevention system. It works by limiting the code that can run on a desktop, rather than identifying and blocking malware before it gets to a system. Its new tools simplify management, but it is daunting to start to work with. The tools resolve some problems associated with a least-privileged user desktop environment, since only applications approved by the administrator are allowed to run. A locked-down desktop generally keeps users from getting into trouble, but the potential remains for malware to be run under users' credentials or for vulnerabilities to be exploited. Parity 3.5 IPS effectively complements a locked-down desktop because it keeps malware inert. The product limits the 'attack surface' associated with running unapproved and vulnerable applications. Alerts are triggered if untrusted or unknown code is observed to be propagating through the network. Parity 3.5 does not clean inert malware from infected systems, however. Users need other tools to accomplish this. Parity 3.5 began shipping in December 2006. It also provides new enhancements for monitoring software usage across an enterprise, controls the utilization of USB storage devices, and gives administrators in-line integration with ParityCenter, also from Bit9, which is a software vetting service. The product can be licensed as a perpetual model or as a subscription model.