Apple is an American multinational technology company that designs, develops, and sells consumer electronics, computer software, and online services. Headquartered in Cupertino, California, Apple is considered to be one of the Big Four technology companies, ranking No. 3 in the 2019 Fortune 500 list of the largest United States corporations by total revenue. Apple offers personal wearable devices, apps, and other technology that has capabilities of monitoring and tracking sleep. Apple acquired Beddit, which produces sleep-tracking sensors that strap on to a mattress, in 2017.