Fitbit just rolled out a small but significant update that gives Fitbit users the ability to use multiple devices on the same account. A person could wear a Fitbit Flex to work and then a Fitbit Surge at the gym. You know, business during the day and party at night.

This functionality is part of Fitbit’s goal to sell multiple devices to a single person. Sometimes, like while sitting in an office cube, a person doesn’t need all the fitness-focused features of the Surge — or want to deal with the bulky form of the $250 watch. This new feature is the perfect solution that also allows Fitbit to sell more devices.

Early last year I sat down with Fitbit CEO James Park where he laid out his company’s plan to get people to buy multiple Fitbits. It boils down to selling Fitbit devices for different situations. For instance the Flex and Zip are a marketed as discrete activity trackers where the Surge is sold as a hardcore tracker for fitness fanatics.

The key to Fitbit’s long term success lies in selling devices. This update essentially doubles the company’s potential market since now a Fitbit user can now buy and use more than one tracker at a time.

The multi-device update is expected to hit later this week.