Technology that fits your life
Premium Titanium Build
Sleek, fully-titanium build under 4 grams with discreet sensors for comfortable 24/7 wear.
7-Day Battery
Up to 7 days of battery life per charge, so you never miss a beat tracking your health.
Privacy by Design
Sentry is independently owned, has no government contracts, and will never sell your personal health data.
Everything your ring knows
Track over 50 health and wellness metrics and get personalized insights into your sleep, activity, heart health, and recovery. Automatic syncing turns your data into clear trends and a daily readiness score, so you always know what your body needs.
Find Your Perfect Ring Size
Measure your finger in under 30 seconds to find your perfect fit.
Measure Your Finger
Wrap a non-stretch string, dental floss, or thin strip of paper around the base of your finger. Mark where the ends meet. The fit should be snug but comfortable.
Measure the String
Lay the string flat and measure its length in millimeters using a ruler. Compare that measurement with the size guide to find your ring size.
Between sizes? Choose the larger size for the most comfortable fit.
Size 7
17.3 mm diameter
54.3 mm circumference
Size 8
18.1 mm diameter
56.9 mm circumference
Size 9
18.9 mm diameter
59.5 mm circumference
Size 10
19.8 mm diameter
62.1 mm circumference
Size 11
20.6 mm diameter
64.6 mm circumference
Size 12
21.4 mm diameter
67.2 mm circumference
Size 13
22.2 mm diameter
69.8 mm circumference
What's Included
Everything you need to get started.
- Sentry Smart Ring
- Magnetic charging cable
- Charging Case
- USB-C cable
- Quick-start user manual
- Sentry companion app access
Tech Specifications
Engineered for accurate, all-day wear.
- Sensors
- Red & infrared LEDs (SpO2), green & infrared LEDs (heart rate / HRV), temperature sensor, accelerometer
- Battery Life
- Up to 7 days; charges in 60–90 minutes
- Materials
- Scratch-resistant titanium, under 4 grams
- Water Resistance
- Safe for showering and swimming
- Connectivity
- Bluetooth Low Energy, iOS & Android
- Compatibility
- Sentry app on iOS and Android
Frequently Asked Questions
Customer Reviews
Sentry Smart Ring
Verified Purchase
"Fantastic ring. In my opinion I highly recommend it, for all the functions it has, I like that it counts my steps, the calories I burn and also my hours of sleep, so I can control my rest time; I love the color. My son also used it and wants one as a gift, I will order it for him soon."
Lauren M.
Sentry Smart Ring
Verified Purchase
"It arrived in the correct size and is easy to install. It works very well, and the battery lasts a long time."
Julio C.
Sentry Smart Ring
Verified Purchase
"Really impressed with the Sentry ring so far. It’s lightweight, comfortable to wear all day, and the sleep tracking has been very useful. I also like that it’s waterproof and easy to set up. You dont need a subscription and its way more affordable than other brands."
Yelena E.
Sentry Smart Ring
Verified Purchase
"Battery lasts longer than i thought and the app was easy enough to set up. great price can do all the same things as oura rings"
Kevin H.
Sentry Smart Ring
Verified Purchase
"Battery lasts longer than i expected and way more comfortable to sleep with than a watch."
James R.
Sentry Smart Ring
Verified Purchase
"Great value for the price. Setup was simple, and the app connected without any issues. It has helped me better track my daily activity and has worked very well so far. The battery life also exceeds my expectations."
Kristen D.
Sentry Smart Ring
Verified Purchase
"Super lightweight i forget im wearing it most days. So far so good"
Noah B.