Apple's long-awaited AirPod wireless earphones have finally gone on sale. They can be bought online from today, 13 December, and will be available to purchase in Apple Stores from 19 December.

AirPods were first announced alongside the iPhone 7 and 7 Plus at an Apple press event on 7 September. The wireless earphones are Apple's answer to the iPhone 7 not having a headphone jack.

But manufacturing setbacks caused the AirPods to be delayed well beyond their original October release date. Apple released a statement to the press explaining the delay: "We don't believe in shipping a product before it's ready, and we need a little more time before AirPods are ready for our customers."

What aspect of the earphones needed more development time is not known for sure. However, a person "familiar with the development" of the product suggest to the Wall Street Journal that the way the earphones both receive their own Bluetooth signal from an iPhone, Mac or other Apple product could have been troublesome. Other Bluetooth earphones work by the sound being sent to one earphone, then passed along from there to the other.

Another problem reported by insiders centered on the AirPods initial inability to transmit a user's voice clearly through the embedded microphone without picking up excessive background noise.

The AirPods, which look very similar to the earphones Apple includes with the iPhone, just with the cable missing, are said to offer far higher audio quality than their wired siblings. And so they should, given the £159 price tag. For that you get the two earphones and a charging case.