Apple on Tuesday made available its wireless AirPod headphones through its website, but within a few hours, the AirPods went from a December 21st delivery to a four week delay.

Apple said delivery of AirPods would start next week along with sales at Apple Stores, Apple-authorized resellers and select carriers. The company had also confirmed that AirPods would be shipping in limited quantities at launch.

Apple unveiled the AirPod, which is priced at $159, at the launch of the latest iPhone in September.

AirPods are packed with high-quality audio and long battery life. With AirPods, setting up and using wireless headphones has never been easier. Just open the charging case near your iPhone and with a simple tap, AirPods are immediately set up with all the devices signed into your iCloud account, including your Apple Watch, iPad and Mac. Sensors detect when AirPods are in your ear and can automatically play and pause your music. Double tapping on AirPods activates Siri, allowing you to access your favorite personal assistant to select and control your music, get directions, make and receive calls or perform any other Siri task.

iPhone recognizes when AirPods are near, making setup as simple as a tap.

This experience is enabled by the new low power Apple W1 chip, which enables AirPods to deliver high-quality audio and long battery life in a completely wireless design. AirPods deliver up to five hours of listening time on one charge while the custom-designed charging case holds additional charges for a total of more than 24 hours of listening time.

The headphones require Apple devices running the latest version of iOS 10, watchOS 3 or macOS Sierra.

The launch delay was widely seen as a rare marketing slip-up by the company, coming as it did just before the start of the holiday shopping season.

Apple had said it needed more time to make the device ready before putting it on the market.