Before a medical device can be legally sold in the U.S., the person or company that wants to sell the device must seek approval from the FDA. To gain approval, they must present evidence that the device is reasonably safe and effective for a particular use, the "indication." Once a device is approved, other similar devices may be cleared by the FDA for use. This requires less information since an equivalent device has already been shown to be safe and effective. In some cases, devices that were on the market before FDA started regulating medical devices may be cleared. Once the FDA has approved or cleared a medical device, a doctor may decide to use that device for other indications if the doctor feels it is in the best interest of a patient. The use of an approved or cleared device for other than its FDA-approved indication is called "off-label use.