The all-new Fitbit Alta HR heartbeat tracker is the world's slimmest variant to date.

Nearly half a year since Fitbit Charge 2 was launched, a more stylish model arrives with a sexier band and longer battery life. As a refresher, the Charge 2 offered a tap-sensitive, OLED display with five-day power supply. The Fitbit Alta HR, meanwhile, thrives with a sleep tracker with heart rate sensors.

Fitbit Alta HR: Longer battery life

According to CNET, the Fitbit Alta HR has a battery that lasts for up to seven days on a single charge. Apparently, this is the main feature of the new heartbeat tracker. It is now available for preorder.

The Fitbit Alta HR will retail for the same price as the Charge 2. Fan theories claim that the value sits around £130, which is equivalent to $150. Most likely, the Alta HR will arrive sometime in April.

Per the same source, the Alta HR features a sleep tracker too. Dubbed as the Sleep Stages, it utilizes the optical heart rate sensor to estimate the time users spent in light, deep, REM nap cycles. Fortunately, this spec will also be coming to the Charge 2.

Other specs of the Fitbit Alta HR

The Verge reported that the Fitbit Alta HR has been developed for almost a year. Shelten Yuen, the company's R&D Director, said that the latest device is 25 percent smaller than its predecessor. Fitbit reportedly worked with Texas Instruments to shrink the heart rate monitor.

Meanwhile, the Fitbit Alta HR has replaceable wristbands that can record steps, distances, and calories burned. Interestingly, it displays notifications for incoming calls, calendar alerts, and text messages. The Alta HR detects the user's activities like running and biking.

Nevertheless, it the Fitbit Alta HR lacks a button. Thus, owners cannot manually start a workout like how they do on the Charge 2. Lastly, it does not have the guided breathing sessions that list the number of floors users have climbed.