On July 20, 2011, the FDA issued both a final rule and a guidance document regarding the classification of Focused Ultrasound Stimulators for Aesthetic Use as Class II Special Control devices. The final rule indicated that the special control(s) that will apply to the device is the guidance document entitled "Class II Special Controls Guidance Document: Focused Ultrasound Stimulator System for Aesthetic Use." Adherence to the recommendations described in the guidance document, in addition to the general controls, will provide reasonable assurance of the safety and effectiveness of focused ultrasound stimulator system for aesthetic use classified under 878.4590 (21 CFR Part 878). In order to be classified as a class II device under 878.4590, an ultrasound stimulator for aesthetic use must comply with the requirements of special controls; a manufacturer must address the issues requiring special controls as identified in the guidance, either by following the recommendations in the guidance document or by some other means that provides equivalent assurances of safety and effectiveness. While the rule is final, comments on the guidance document may be submitted at any time to FDA.