More details are emerging about Apple’s forthcoming watch, which is targeted for release this year, according to a Bloomberg report this morning and corroborated by our sources. Bloomberg says the watch project has long been a favorite of Apple design chief Jony Ive, who reportedly ordered “boxes” of Nike sports watches for his team to study a few years ago.

That’s perfectly in line with what we’ve heard about the watch project, which we’re told is being led by Ive himself with some 100 engineers under him. Interestingly, we’re also told that Apple’s chosen to rework the full iOS to run on the watch instead of building up the iPod nano’s proprietary touch operating system — although the previous nano was already watch-sized and seemed like a great starting point for a wrist-sized device, Apple’s betting on iOS across product lines.

That’s apparently leading to battery life issues in development, according to our sources: the goal is to last at least 4-5 days between charges, but the current watch prototypes are apparently only going for a couple days max.

More: Apple’s Watch Will Run iOS and Arrive Later This Year, Say Sources