Withings on Monday added a third wearable to its Activité line of fashion-first activity trackers. The Activité Steel is indistinguishable from an ordinary watch but in actuality, it's continually keeping tabs on a number of fitness-related metrics.

The wearable features a 1.3-inch round face that's water resistant up to a depth of 165 feet and what Withings calls a "day & night" motion sensor. There are just two dials on the watch's face; the primary dial shows the time while the sub-dial shows the percentage of daily activity goal reached.

Along with a high-precision MEMS 3-axis accelerometer, the Activité Steel is able to track steps, distance, calories, running and swimming. The device can even log how long it takes for its wearer to fall asleep, duration of sleep, light and deep sleep cycles and sleep interruptions.

All interactions with the Activité Steel take place in the companion mobile app, Withings Health Mate, for Android and iOS devices. Because there's no display or other fancy (some would say "unnecessary") features, the watch doesn't require frequent recharges. In fact, it's powered by a standard CR2025 button cell that offers up to eight months of life. Withings does note, however, that daily use of the watch's vibrating alarm will significantly reduce the lifespan of the battery.

The Activité Steel is available as of writing in a classic black finish for $169.95 on Withings' website.