• Fitbit Charge 4
• Classic wristbands (both small & large)
• Charging cable

• Fitbit Charge 4
• Woven reflective band (both small & large)
• Classic wristband (both small & large)
• Charging cable

• 3-axis accelerometer
• Optical heart rate monitor
• GPS + GLONASS
• Red and infrared sensors for oxygen saturation (SpO2) monitoring
• Device temperature sensor (skin temperature variation available in the Fitbit app)
• Vibration motor
  
• NFC
• Altimeter

Battery life up to 7 days, or up to 5 hours with continuous GPS use. Battery life and charge cycles vary with use, settings, and other factors; actual results will vary. We recommend charging every few days to ensure you’re always tracking.

• Battery type: Lithium-polymer
• Charge time (0-100%): Two hours
• Radio transceiver: Bluetooth 4.0

• Saves 7 days of detailed motion and heart rate data, minute by minute
• Saves daily totals for past 30 days
• Measures heart rate data at 1-second intervals during exercise tracking and at 5-second intervals all other times

Water resistant to 50 meters. After swimming or getting the band wet, we recommend drying the band because, as with any wearable device, it's best for your skin if the band is clean and dry. We do not recommend wearing Fitbit Charge 4™ in a hot tub or sauna. 

Give your wrist a rest by taking the band off every now and then. If the band gets wet or you sweat in it, remove and completely dry the band before putting it back on. 

This tracker includes a plastic resin case and the band includes a stainless steel buckle. The classic band is made of a flexible, durable material similar to that used in many sports watches. The woven band is made from a comfortable polyester.

Like all heart rate tracking technologies, accuracy is affected by physiology, location of device and different movements.

• Operating temperature: -4° to 140° F
• Maximum operating altitude: 28,000 feet

Syncs automatically and wirelessly to most popular phones and tablets using Bluetooth LE wireless technology.

• Syncing range: Up to 30 feet
• Certain features like smartphone notifications may require Android 7.0+
• Syncing to mobile devices requires Bluetooth LE and internet connection.
• Syncs with Mac OS X 12.2 and up, iPhone 5S and later, iPad 5 gen. and later, Android 7.0 and later.
• Music control via Bluetooth LE on Android and iOS devices.

Small

• Fits wrist 5.5" - 7.1" in circumference

• Fits wrist 7.1" - 8.7" in circumference

• 1.4in l x 0.9in w x 0.5in h