Aura Strap 2 review: context — you love to see it

Body composition analysis is a new feature for Wearables. The feature was the first to be included on the watch. The first fitness tracker to feature the feature was Amazon's Halo Band. The two launched in the past two years. Apple hasn't tackled body composition yet. The Aura Strap 2 is an accessory for Apple Watch owners.

Like smart scales, the Aura Strap 2 determines your body composition using bioelectric impedance analysis. BIA works by sending a weak electric current through your body to calculate your body fat percentage, lean muscle mass, water, and sometimes niche metrics like bone mass. This particular strap measures fat, muscle, water, Visceral fat, lean mass, and minerals, a proxy for bone mass.

Compared to the first iteration of the device, this one is 20 percent slimmer and 5 percent narrower. The measurement process has been simplified. If you touch your palm to the strap's electrode, you will be able to take only three steps. According to Aura Devices, these design changes enable Aura to record 16 times more data, and the second-gen strap delivers about 95 percent accuracy compared to a DEXA Scan.

The Aura Strap 2 changes how you put it on. Instead of clasps, it opts for a stretchable band that resembles Apple's solo loop band. That can be either pro or con. If you are using the Apple Watch for health tracking, then you are already aware of how important the fit is. You want the BIA sensor to rest against your skin, because loose fits make for inaccurate metrics. It is harder to do with a stretchy band. The Aura strap 2 comes with a medium-sized strap, as well as three additional sizes in extra small, small, and large. The small strap did not fit my bird wrists. The small did not. The extra small wrists did the trick, though I have friends with even smaller wrists. There is no way to adjust the strap if your wrist doesn't fit one of the straps.

It was difficult to stretch over my hands because the extra small band fit my wrist. I have larger hands than average, and there is only so much you can stretch the strap. My fingers can stretch nine keys on a piano, and I can use an iPhone 12 Pro Max single-handed. The company says it's safe to take it into the shower and pool, so you don't have to take it off more than once a day. I kept it on to avoid taking the strap off, because I normally take off my Series 7 to shower. I didn't like taking the strap off at night. I will admit that it is a problem that is specific to my body, but it is something to be aware of if you have large hands.

To change strap sizes, you have to open the battery and electrodes in the case. You can't simply open it with your fingers. If you're like me, you'll probably lose the strap within seconds if you wedge it open. You can use a credit card. It isn't likely to be a huge issue beyond setup and when you need to replace the battery, if you need to try multiple bands to find your correct size. If you take a single reading per day, the coin cell battery should last six months. I don't know if that's true, as I haven't been using the strap for a long time. I have about 76 percent left after about a week of testing.

The Aura Strap 2 is easy to use. There are instructions on how to take a measurement in the app and on the watch. You can take a reading with the Aura app open on your watch. Aura suggests that you stand with your arms out in front of your chest, like you are about to do a Russian squat dance.

This is a huge improvement over the previous watch. I was given a laundry list of things I had to check to get an accurate reading after I reviewed the BIA feature on that watch. I had to make sure I wasn't menstruating or wearing jewelry. If you wore the watch on your right wrist, it was hard to use as you had to reach around to get the buttons. There were no issues with the Aura Strap 2. I didn't have to worry about my period, my jewelry, or which wrist I wore the Series 7 on, as Apple lets you change the orientation of your watch.

From reading to reading, my results were the same. They correspond to the results I got on theGalaxy Watch 4. The Aura app gave me a better idea of how the metrics related to each other. I have been told by every other device that I am overweight or obese. Body fat percentage is more useful than the body mass index. My waist-to-hip ratio, a method of measuring your risk of heart disease based on your abdominal fat, is within a normal range. My smart scale puts me at 31 percent body fat. These devices can help you measure progress, but they may not be accurate when it comes to your health.

I was impressed when the Aura app said that I had a good balance of fat and muscle, even though my body fat percentage was above normal. I appreciated how the app described the metric. My fat percentage was 1 percent. Normally, I would think that's an excellent thing. It was noted by the app that if myVisceral fat was out of range for a sustained period of time, I might not have enough for my bodily needs. It was explained that the norm was based on the general population and did not take into account my individual metabolism, lifestyle choices, or my personal norms.

If you have a specific body goal such as losing weight or getting jacked, the Aura app will help you get there. My goal was to have a body with muscle gain. I was told by the app that I should increase my intake of calories by 10%, add more calories to my diet, and do no more than three workouts per week.

The best part is that the app doesn't focus on weight. If you set your goal to lose fat, it never recommends that you lose weight.

I didn't like that a lot of it is locked behind a paywall. If you want monthly reports on fitness and nutrition, guided workouts, or an upcoming feature that lets you chat with a personal trainer, you have to pay a monthly fee. I can't say if the extra fee is worth it. The workout library I had access to was easy to use but limited to one workout per body area and skill level. I have only been testing for a couple weeks and didn't get the full monthly report experience. $150 is already spent on an accessory. It makes sense to add a subscription, but it's still another thing to pay. People who would be inclined to buy this device already pay for multiple fitness-related subscriptions.

I was pleasantly surprised by the Aura Strap 2. It's not perfect, but it's not impossible. This is a better app that offers context and insights. It's a niche product, but if you're an Apple Watch owner, you're interested in changing your body composition? You could do worse.

Victoria Song is a photographer.

Every smart device now requires you to agree to a series of terms and conditions before you can use it. It is impossible for us to read and analyze all of these agreements. We started counting how many times you have to agree to use devices when we review them.

To use Aura Strap 2, you have to pair it with an Apple device. The phone's terms of service, privacy policy, and health data policy are included. You will need to sign up for an Aura account and grant additional permission for certain things.

You agree to two mandatory agreements if you set up the Aura Strap 2.

• Aura Device’s Terms of Use
• Aura Device’s Privacy Policy

There are two mandatory agreements for your phone and the Apple Watch.