Nokia-owned Withings has unveiled its latest activity-tracking wristwatch, the Steel HR. It offers users fitness tracking, a heart rate monitor, and smartphone notifications — all within a stylish, metal design with a 25-day battery life. And yes, it tells the time, too. The Steel will go on sale in October, and is available in two sizes (36 millimeter and 40 millimeter) for $179.95 and $199.95, r