Apple sold $5.5bn worth of 'other' hardware products - inc watches and earpods - in Q4 2017

"Other than its iPhones and computers, Apple sells a bunch of other products, like the AirPods, Apple Watch, Apple TV, Beats products, iPod Touch and, most recently, the HomePod. In Q1 2018, Apple saw $5.5 billion in revenue for these other products, an increase of 36 percent year over year.
That increase suggests Apple’s Watch Series 3, which it launched this past September, and its AirPods are selling well.
In Q4 2017, Apple sold just $3.2 billion worth of other products. To be clear, these revenues do not include pre-sales for the HomePod, which starts shipping February 9 for $349."

Source:  Techcrunch, 1st February 2018
Plus - Apple has an installed base of 1.3bn active devices