Withings' assault on our paunchy bellies doesn't look like it's going to stop, now that the company has launched a portable sleep and activity tracker that's clearly designed to go after the Fitbit Ultra. The Smart Activity Tracker makes some impressive claims, offering pulse monitoring if you push your finger onto the back of the device, calculating calorie consumption and monitoring the quality of your sleep. The 43.3 millimeter device has an OLED touchscreen display and will instantly upload your data to the
