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Lunar white aluminium smartwatch with white silicone band, square AMOLED display

Fitbit

Fitbit Sense 2 Smart Watch FB521SRWT-US Lunar White Platinum Aluminium

SKU CH-9A3C-06MT8 MPN FB521SRWT-US

Advanced health smartwatch with cEDA stress detection, ECG app, SpO2 monitoring and built-in GPS, plus six-day battery life and both band sizes included

  • ColorLunar White
  • TypeSmart Watch
  • Case MaterialAluminium
  • Band MaterialSilicone
  • Band LengthBoth small and large sizes included in box. Small: Fits wris
  • Display TechnologyAMOLED

Color Lunar White

  • Tracks health stats for 6+ days per charge
  • 12-minute charge adds a full day of use
  • Built-in GPS maps workout intensity without phone
  • cEDA sensor gives daily Stress Management Score
  • ECG app checks for atrial fibrillation signs

Advanced health smartwatch

The Fitbit Sense 2 is a health-focused smartwatch built with an aluminium case and AMOLED display. It is designed for users who want continuous stress, heart-rate and sleep insights alongside everyday smartwatch functions. A Google account and the Fitbit app on a compatible phone are required for setup and ongoing use.

6-plus day battery and on-device storage

The battery delivers six or more days of typical tracking, though always-on display, SpO2 and the cEDA sensor reduce that span. A quick 12-minute charge adds a full day of runtime. Internal memory holds seven days of minute-by-minute motion data before the oldest records are overwritten.

Two band sizes and Fitbit Premium trial

Both small and large classic silicone bands ship in the box, covering wrist circumferences from 5.1 to 8.6 inches. The package also includes a proprietary charging cable. Buyers receive a six-month Fitbit Premium membership that unlocks guided workouts, mindfulness sessions, Daily Readiness Scores and deeper sleep analysis.

Highlights

  • Tracks health stats for 6+ days per charge
  • 12-minute charge adds a full day of use
  • Built-in GPS maps workout intensity without phone
  • cEDA sensor gives daily Stress Management Score
  • ECG app checks for atrial fibrillation signs

Specifications

BrandFitbit
ModelSense 2
Part NumberFB521SRWT-US
ColorLunar White
TypeSmart Watch
Case MaterialAluminium
Band MaterialSilicone
Band LengthBoth small and large sizes included in box.
Small: Fits wrist 5.1 - 7 inches in circumference
Large: Fits wrist 6.5 - 8.6 inches in circumference
Display TechnologyAMOLED
Built-in StorageSaves 7 days of detailed motion data, minute by minute
Battery LifeBattery life of 6+ days. Battery life and charge cycles vary with use, settings and other factors; actual results will vary. Use of the always-on display, SpO2 and the cEDA sensor will require more frequent charging. Up to 5 hours with continuous GPS. We recommend charging your tracker every few days to ensure you are always tracking.
SpecificationRequirements:
Google account will be required.
The Fitbit app is compatible with most popular phones. To set up and use your Fitbit products and services, you must install the Fitbit app on a compatible device running one of the following operating systems:
Apple iOS 15 or higher.
Android OS 10 or higher. See additional tips for Android phones here.
Syncing range: Up to 30ft
Certain features like smartphone notifications may require Android 10+.
Syncing requires Bluetooth® LE, an internet connection and location permissions granted on the phone
FeaturesMulti-path optical heart rate sensor
Electrical sensor to measure skin conductance (cEDA) for body response tracking
Multipurpose electrical sensors compatible with ECG app & EDA app. ECG not available in all countries.
Red and infrared sensors for oxygen saturation (SpO2) monitoring. Not available in all countries. Not intended to diagnose or treat any medical condition or for any other medical purpose. Intended to help you manage your well-being and keep track of your information. Requires more frequent charging.
Gyroscope
Altimeter
3-axis accelerometer
Skin temperature sensor. Onl
HeightHeight: 0.44 in (11.2 mm)
WidthWidth: 1.59 in (40.5 mm)
DepthLength: 1.59 in (40.5 mm)
Weight0.08 lb (37.64 g)
Package ContentFitbit Sense 2
Classic band (small & large)
Charging cable
Shipping weight0.26 kg
Package size40 × 40 × 12 mm

Other versions of this model

1 more in the same range

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Questions about this item

Will the Fitbit Sense 2 pair with the older Android phone I still use daily?

The Fitbit app works with most popular phones; a Google account is required for setup and ongoing use.

How can I confirm the cEDA sensor is tracking stress correctly after I put the watch on?

Open the Fitbit app to view your daily Stress Management Score and real-time body response graph generated by the electrical sensor.

Does the box include both band sizes and the charger, or must I buy a large band separately?

The package contains the Sense 2 watch, classic silicone bands in both small (5.1–7 in) and large (6.5–8.6 in) sizes, and a charging cable.

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