Fitbit on Monday refreshed two of its most popular fitness-tracking wristbands with the introduction of the Charge 2 and Flex 2.

The Fitbit Charge 2 sports a new design that affords a 4x larger display and interchangeable bands. Thanks to continuous heart rate tracking, wearers can get a snapshot of their cardio fitness level based on estimated VO2 Max (maximum volume of oxygen). There’s also a new deep-breathing feature called Relax that offers two- and five-minute sessions designed to help reduce anxiety and stress.

Elsewhere, the Charge 2 can track specific workouts such as running, yoga and weightlifting, monitor sleep and remind users to move if you’ve been sitting idle for too long. There’s no onboard GPS functionality although if you link the Charge 2 to your smartphone (and have it on you), it can provide more precise and actionable real-time stats as well as record a map of your route.

The Flex 2, meanwhile, is 30 percent smaller than its predecessor and is the company’s first swim-proof wristband. It doesn’t include a true display nor does it have a heart rate sensor but that’s not surprising given its price point.

What you do get, however, is a modular module that can snap into a number of different accessories. Like the Charge 2, the Flex 2 will also remind users to move and automatically recognizes select workouts such as swimming, riding, running and even sports and elliptical machine usage.

The Fitbit Charge 2 and Flex 2 are available to pre-order as of writing, priced at $149.95 and $99.95, respectively. Look for the Charge 2 to arrive with your choice of black, blue, plum or teal fitness band by mid-September. The Flex 2 will come with a black, lavender, magenta or navy band once it lands in October.