The Missile Technology Control Regime (MTCR) is an informal and voluntary association of countries that share the goals of nonproliferation of unmanned delivery systems capable of delivering WMDs and that seek to coordinate national export licensing efforts aimed at preventing WMD proliferation. MTCR rests on adherence to common export policy guidelines that are applied to an integral common list of controlled items. The greatest restraint (i.e., "a strong presumption of denial") is applied to what are known as "Category I items." These items include UAS with capabilities exceeding a 300 km/500 kg range/payload threshold, the production facilities for such systems, and any major subsystems.