Conformance testing or type testing is testing to determine whether a product or system meets some specified standard that has been developed for efficiency or interoperability. To aid in this, many test procedures and test setups have been developed, either by the standard's maintainers or external organizations, specifically for testing conformance to standards. Conformance testing is often performed by external organizations, which is sometimes the standards body itself, to give greater guarantees of compliance. Products tested in such a manner are then advertised as being certified by that external organization as complying with the standard. Service providers, equipment manufacturers, and equipment suppliers rely on this data to ensure Quality of Service (QoS) through this conformance process.