(Pocket-lint) - Fitbit has announced three new devices, the Fitbit Charge, Charge HR and Surge.

The Surge is the new top-of-the-line, a fully-fledged sportswatch that offers so much more than just movement tracking. It's the most sophisticated Fitbit device so far and looks to take on the likes of Garmin or TomTom. 

The Fitbit Surge has a GPS, wrist-based heart rate tracking and motion sensors, as well as offering smartwatch functions like caller ID, music control and message alerts.

It has a LCD display and promises to give you 7 days of battery life, with Fitbit making a point of stating that you'll be able to track your working week, or an entire marathon, on one charge. 

It will also support multisport activities and strength training, so really sees Fitbit moving into sportswatch territory properly. The Surge offers all the functionality of the Fitbit Charge devices, also announced.

The Charge models are sportsbands with various functions, an evolution of the Fitbit Force. 

The Charge is equipped with an OLED display, offering you movement and sleep tracking, as well as a connection to your smartphone so you get caller ID.

You'll be able to keep up with your exercise targets, all tracked on the Fitbit dashboard or though the smartphone app.

The Charge HR adds Fitbit's PurePulse optical heart rate reader, taking your pulse from your wrist for constant monitoring.

The heart rate information will be gathered along with all the other stats that the regular Charge monitors for a complete picture of your daily activity.

Adding heart rate monitoring on the Charge HR sees a 2-day reduction in battery life, however, as the Charge HR will give you 5 days of life, compared to the Charge's 7-day life. 

The Fitbit Charge is priced at $129.95 and will be available in black, white, blue and burgundy, available in the US now. UK pricing and availability are to be announced.

The Fitbit Charge HR will be $149.95, available in black, plum, blue and tangerine and will be coming in early 2015.

The Fitbit Surge will be $249.95 in black, blue and tangerine, available early 2015.

We'll update the details as soon as we have prices for the UK.

Writing by Chris Hall.