Fitbit Charge

Activity and sleep tracking wristband

Fitbit Charge is more than a replacement for the Fitbit Force. It also has an improved band that washes clean more easily, an improved clasp that keeps it more secure on your wrist, and automatic sleep detection.
This looks interesting, but after my experiences with the Fitbit Flex and Fitbit support, I'll never buy or recommend another Fitbit product. They just don't last at all - the Flex needed replacing at least every four weeks. :(