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 Withings Health Mate app over Bluetooth Smart, and promises to go a full fortnight without needing a recharge. The company hasn't made any statement as to when it plans to release the unit, or how much it'll cost you, but we're looking forward to putting it through its paces. Follow all the latest CES 2013 news at our event hub.