New research has found that Apple has sold around 2.79 million units of it’s Apple watch as of mid-June, and is making additional profits through the sale of its band accessory.

The report suggests that around 20% of Apple Watch buyers have also bought a spare band that can be used to match with different outfits and suite different occasions.

Reuters cited the study conducted by research farm Slice Intelligence, which studies e-mail receipts from a panel of 2 million online shoppers in the US.

Out of those who were surveyed, nearly 20,000 of them bought the Apple Watch and 17% of them bought more than one band.

Apple Watch customers have reportedly made the black sport band as their preferable choice as it topped amongst device purchases and additional band sales, followed by the $149 Milanese loop.

According to tech research farm HIS, the $49 entry-level sports band only costs around $2.05 to manufacture, excluding packaging and shipping charges, which indicates the level of profit the company might be making by selling the accessory.

The iPhone maker has also opened doors for third-party developers to design bands for the Watch. According to reports, if the third party bands succeed then it could have negatively impact Apple’s own accessories.