The FDA approved Boston Scientific’s non-valvular atrial fibrillation device after the company spent years trying to secure an approval.

The Watchman is “a left atrial appendage closure device” that can be used as an alternative treatment to blood thinners.

The device is only approved for warfarin-eligible candidates who “did not have an appropriate rationale to seek a non-pharmacologic alternative to warfarin,” Medpage Today reported.

The Wall Street Journal noted in an October 2014 story following an advisory panel’s 6-5 endorsement that the Watchman is a one-inch plug that is meant to keep possible blood clots from making their way into arteries and causing strokes. Cowen Group analyst Joshua Jennings told the Journal at the time that the device was important for investor sentiment and that a US approval could move sales from $41 million in 2014 to $170 million by 2018.

The device has had varying levels of endorsement. Forbes reported in June that the FDA told Boston Scientific the Watchman would have to go through a third advisory panel vetting. An FDA panel recommended the device in 2013 but some panel members expressed concern about the device and the potential for overuse, Forbes added. This is in addition to a 2010 complete response letter from the FDA asking for additional safety and efficacy data.