JYUAJOI 1.47-Inch Fitness Tracker

That spare band is more useful than it sounds. A strap that has just been through a sweaty workout is not what you want against your skin in bed. Swap to the dry one, rinse the first, and the tracker stays on the wrist all night.

The tracker itself measures about 1.5 x 0.9 x 0.4 inches in a metal-and-plastic body. It is a band, not a watch slab, and that shape suits people who find big square watches bulky on a thin wrist or under a shirt cuff.

The 1.47-inch colour screen is curved, following the line of the wrist. More than 200 watch faces sit in the companion app, and you can set a photo as the face to match a mood or an outfit.

What you see at a glance:

• the time, date and your step count
• live heart rate on the screen
• call and message alerts from the phone
• the weather before heading out

The JYUAJOI shows call alerts but does not take calls, so the phone still handles the conversation. For wrist calling, look at the calling watches in the alternatives, such as the STECEi T50S.

A range is easier to read than one number. If a single figure looks odd, the average usually tells you whether it was a loose strap or a genuine dip. Keep in mind that a wrist band gives wellness trends, not medical results.

Heart rate runs continuously and appears live on the screen. The app turns the history into dynamic charts, useful for seeing how a calm week compares with a busy one.

A morning check-in routine:

1. Open the sleep summary: light sleep, deep sleep and wake times.
2. Look at last night's SpO2 average and range.
3. Note the resting heart rate.
4. Pick today's effort: a hard session, an easy walk, or rest.

Steps, sport modes and gentle reminders

Activity reports cover daily steps, active minutes and calories. For workouts there are 24+ sport modes, with steps, distance, calories and heart rate tracked live during the session.

• Sedentary reminder: a nudge after long periods sitting.
• Breathing exercises: short guided sessions to wind down.
• Female health tracking: cycle dates and reminders in the app.

The shorter mode list keeps the band simple to use. Walking, running, cycling and gym sessions are the everyday staples, and most people use three or four modes week in, week out. Put those at the top of the menu in the app, and starting a session takes two taps with a sweaty finger.

For a closer look at how wrist sensors handle SpO2 and sleep, the health tracking review has the details.

That Android 10 line matters if you plan to pair it with an older spare phone or a parent's handset. Check the Android version in the phone's settings before you order.

1. Charge the tracker for about 2 hours on the supplied cable.
2. Install the companion app named in the JYUAJOI instructions.
3. Turn on Bluetooth and add the tracker from inside the app.
4. Allow notifications for calls and the messaging apps you use.
5. Set your profile and step goal, and switch on all-day SpO2 and heart rate.

If the tracker disappears from the phone, background limits are the usual cause on Android. The stay-paired guide lists the settings to adjust on both platforms.

Charging rhythm

Battery life runs 5 to 7 days on a single charge. All-day SpO2 and a bright screen push it toward the shorter end, so a charge every five days is a safe habit. Pick a fixed evening, charge while you shower and cook, and put it back on before bed.

Charging contacts pick up sweat and skin oils. Wipe them dry after workouts, and if the tracker stops taking a charge, try the steps in the charger guide.

The Runlio T115 is the pick for swimmers thanks to its 5ATM rating. The USMECBL 1.47-inch uses an OLED screen. The Bestinn H32 has a larger face with an always-on clock.

Beyond looks, the JYUAJOI's main trade is calls for comfort. Calling watches carry a speaker, a microphone and a bigger battery, and that adds bulk. A slim band gives those up for a lighter wrist, which pays off at night. If sleep scores and blood-oxygen trends are what keep you motivated, that trade makes sense.

The JYUAJOI suits you when:

• you want SpO2 shown as a range, not just a number
• a spare band for nights and workouts appeals
• your phone runs Android 10+ or iOS 10+

Check before you order:

• It shows call alerts but does not take calls.
• 24+ sport modes is a shorter list than on bigger watches.
• It is IP68, not swim-rated.
• The companion app is not named up front; the instructions list it.

For a slim, light band that keeps heart rate, blood oxygen and sleep in view day and night, the JYUAJOI is a tidy choice. Replacement straps for slim bands are covered in the bands guide.