http://www.wsj.com/articles/apple-watch-faulty-taptic-engine-slows-roll-out-1430339460
Cupertino, Calif. -- Apple will be forced to limit the availability of its highly anticipated Apple Watch after a key component from one of two suppliers was found to be defective, The Wall Street Journal reported. The defective part, called a "taptic engine," is designed to alert wearers by sending a tapping sensation down their wrists. The Journal reported that some units made by China's AAC Technologies, however, began to break down over time. Cupertino-based Apple has since moved nearly all production of the component to Japan's Nidec. The company, which began taking orders for the watch on April 10 and shipped the first units to customers on Friday, reportedly told some of its suppliers last week to slow production until June, without explaining why.