In Apple’s seemingly endless quest to make its products lighter and thinner, the company may have come up with a clever way to save space in future versions of the iPhone and iPad: by using curved batteries that nestle more comfortably into its devices’ contours. AppleInsider has found a pair of Apple patent filings that describe “curved battery cells for portable electronic devices” and “non-rectangular batteries for portable electronic devices” that the publication speculates could be used in future iPads and iPhones.

In one of its patent filings, Apple says that the batteries’ curves were designed “to facilitate efficient use of space inside a portable electronic device” and notes that “the curve may be formed at one or more ends of the battery cell to allow the battery cell to occupy a curved and/or rounded space within the enclosure of a laptop computer, tablet computer, mobile phone” and more. Left unsaid is the fact that curved batteries would also be perfect for Apple’s long-rumored “iWatch” that the company reportedly plans to sell as an accessory to compliment its other mobile devices.