Premarket Approval (PMA) is the FDA process of scientific and regulatory review of a Class III Device. Class III medical devices are those that support or sustain human life, are of considerable importance in preventing impairment of human health, or which present a potential, unreasonable risk of illness or injury. Due to the risk with these devices, general and special controls alone are not enough to ensure safety and efficacy. As such, the device manufacturer must submit a PMA application to demonstrate the safety and effectiveness of its Class III medical devices and must receive approval prior to marketing the device. The FDA grants approval if it determines the PMA contains sufficient valid scientific evidence assuring it is safe and effective for its intended use. This is the heaviest burden for a device manufacturer marketing in the US.