The device has a battery life of up to two weeks, and the screen is a 1.1-inch AMOLED display with touch controls. In addition to the health functions, it can link up to your phone to display notifications, control music playback and other features.
There are three different straps -- black, navy and "tangerine gray" -- but only the black one comes in the box. Getting one of the others will cost about $5.
The device only supports Android at launch, but the company noted that iOS support will be added later.
OnePlus didn't immediately respond to a request for comment about international availability.