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femometer

femometer Smart Ring Gen2 Sizing Kit - Size First Before You Buy - Sizes 6-13 - Choose from 8 Sizes - Find The Perfect Ring Size

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Availability: Only 2 left in stock, order soon!
Fulfilled by Amazon
Arrives Tuesday, Sep 8
Order within 19 hours and 59 minutes
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Color: White


Size: Size6-13


Features

  • Why Ring Sizing Kit - femometer ring sizes are different from standard ring sizes. That's why we offer size kits for you before you buy. femometer Ring Gen2 is available in sizes 6-13.
  • How It Should Fit - Please hold the measuring instrument tightly against the base of your finger and make sure it not rotate freely. We recommend wearing your ring sizer for at least 24 hours to confirm your best fit.
  • Best Accuracy Recommend - When wearing the ring, please make sure the engraved numbers face the back of your hand. For best accuracy, we recommend wearing the femometer ring on your index, middle and ring fingers.
  • The femometer sizing kit is made of high-quality plastic, the femometer ring has a different material composition. While the outer of the femometer ring is made of oxidized ceramic, and the inner is also coated with a scratch-resistant layer to promise excellent quality and durability.

Description

Before purchasing a femometer ring, we recommend purchasing a sizing kit to determine the best size for your finger. It's the ideal way to find the perfect size. Femometer Ring Gen2 is available in 8 sizes from 6-13. Choose your perfect size. Wear the femometer Gen2 Sizing Kit for at least 24 hours to determine your size. After measuring your perfect size, choose your own femometer Smart Ring. Why should I use the sizing kit before ordering my Femometer smart ring? The sizing kit ensures a perfect fit for both comfort and accurate health tracking. An improper fit may cause discomfort or interfere with sensor contact, leading to unreliable data. How does the sizing kit help me choose the right ring size? Test different sizes for 24+ hours (including during sleep/exercise) to account for natural finger swelling. The ideal fit feels snug but allows slight movement and won’t leave pressure marks. Why can’t I use my regular ring size for the Femometer smart ring? Unlike traditional rings, the smart ring has built-in sensors along the inner wall, requiring precise contact with your skin. The sizing kit accounts for this unique design, ensuring the sensors align correctly.

Operating System: Wear OS 2.0


Special Feature: Lightweight


Connectivity Technology: Bluetooth


Wireless Communication Standard: Bluetooth


Battery Cell Composition: Lithium Ion


GPS: No GPS


Shape: Round


Screen Size: 1 inches


Brand: femometer


Style: Ring Sizing Kit


Operating System: Wear OS 2.0


Additional Features: Lightweight


GPS Geotagging Functionality: No GPS


Band Material Type: Oxidized Ceramic


Water Resistance Level: Not Water Resistant


Human Interface Input: Unknown


Shape: Round


Style Name: Ring Sizing Kit


Color: White


Battery Cell Type: Lithium Ion


Connectivity Technology: Bluetooth


Wireless Compability: Bluetooth


Compatible Devices: Smartphone


Compatible Phone Models: Compatible with iOS and Android devices


Brand: femometer


Model Number: IRS-202


Built-In Media: Sizing Kit


Warranty Description: 1 Year Manufacturer


Wearable Computer Type: Smart Ring


Unit Count: 8 Count


UPC: 810115237570


Manufacturer: LOLLIPOP TECHNOLOGY (HANGZHOU) CO., LTD


Screen Size: 1 inches


Display Type: No Display


Warranty Type: Standard/Full


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Sep 8

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

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Top Amazon Reviews

    • Great cycle tracking!
Color: Gold Size: Size6
Review Image by Austin Eckhart
📈 This ring and its app are great. I've had it since January 2026. I got pregnant in May and it tracks my BBT accurately so early on I knew I was pregnant based on my raised temperatures. Also I only need to wear the ring at night which is nice because it clangs against dishes I wash and dumbbells while I'm working out. đŸ€°đŸ‘đŸ‹ It also gives a lot of insight into your cycle and especially your pregnancy. When the app switches to pregnancy mode, it shows a daily developmental fact of the baby, what size "fruit" you are and has so much advice and tools to help me get started on my pregnancy journey. This is my first pregnancy and I'm loving this ring/app to keep tabs on things. đŸ‘ŁđŸ’€ It also tracks steps and sleep. But because fitness tracking is not it's prime job, it's not like an Oura ring, and that's okay. It is still decent at some activity tracking though but I wear a Garmin fitness watch to see actual fitness data. The Femometer is really just best at cycle tracking/info. It's sleep tracking is on par with my Garmin though 👍 ... show more
Reviewed in the United States on August 22, 2026 by Austin Eckhart
    • Love this ring!
Color: Gold Size: Size9
Review Image by Grace
I’ve had this ring for about 6 weeks or so and I love it so far. I wear mine day and night and only charge it every 4ish days. Before writing this review I have verbally recommended it to multiple women. I love the features it has for cycle tracking. You can get in depth analytics for sleep, cycle, ovulation, body temperature etc. I have cross referenced my steps and temperature with other tracking devices and it seems to accurately track. It’s very sleek and comfortable! I like to fidget with mine, so I notice when it’s not on. I ordered a size 9 and wear it on my index finger. ... show more
Reviewed in the United States on August 5, 2026 by Grace
    • Should I be worried?
Color: Gold Size: Size9
So far I absolutely do love the ring! I wear it on my middle finger and grounded the sizing was a little weird overly I'm satisfied with it. But yesterday, the skin of it I guess you can call it begin to peel off I had to use super glue what a dry a little and then put it back in place. Overall though everything is still working fine the charge life is all that great but yeah!. Sleep tracking is very insightful and I would say that it's the connectivity it can be slow at times but it works. Overall I want to say it's pretty accurate though I'm worried about the durability. ... show more
Reviewed in the United States on December 11, 2025 by C.M
    • Dead
Color: White Size: Size6-13
My ring just stopped charging all together. It wouldn’t read my vitals, it stopped pairing to my phone, and then stopped charging. It was not the case because I was able to test that the case was still working. This is an expensive item for it to completely die after two months.
Reviewed in the United States on August 29, 2026 by Grace Valentine
    • Good potential but NOT WATERPROOF!
Color: Gold Size: Size9
Review Image by Dr. Anne
Review Image by Dr. Anne
My first one died after a week or two. It wouldn’t charge or sync, and the ceramic cracked. I requested a replacement. After a brief delay (it was out of stock), the manufacturer sent me a new one. I quickly realized it was not very waterproof- I accidentally forgot to remove it while doing dishes. It had to spend some quality time drying in a bag of rice before it would charge again. The battery is supposed to last a few days. It lasts less than one day, so I can only wear it to bed and remove it during the day, much like a Tempdrop. So the activity tracking doesn’t really matter. The sleep data has trouble syncing with Apple Health. The sleep duration does, but Apple can’t interpret the sleep stage data. See photos. The first one is Apple Health. The second one is the Femometer app. ... show more
Reviewed in the United States on October 19, 2025 by Dr. Anne
    • Sleek design with surprisingly powerful features
Color: Gold Size: Size9
I’ve been really impressed with this smart ring so far. It looks sleek and minimal, but it packs a lot of useful features, especially for sleep and health tracking. The ring is lightweight and comfortable to wear all day and night—I barely notice it’s on, which makes it perfect for sleep tracking. The ceramic finish also gives it a premium look and feels very durable. The data it provides is clear and helpful, especially for tracking sleep quality and overall activity. It’s nice to have something more discreet than a smartwatch while still getting meaningful insights. Battery life has been solid, and charging is simple and quick. The app is also easy to use and makes it easy to understand your stats without feeling overwhelming. Overall, this is a great option if you want a stylish, low-profile wearable that still delivers on performance. Definitely worth it. ... show more
Reviewed in the United States on April 7, 2026 by Shelby
    • Awesome Ring
Color: Gold Size: Size7
Review Image by HoneyVixenn
The ring came quickly! It has done an amazing job tracking my sleep and BBT. The app is so simple to use and gives great explanations and analysis. It fits so comfortably and I sometimes forget I’m wearing it. I also went with my regular ring size and it fits accurately!
Reviewed in the United States on August 5, 2026 by HoneyVixenn
    • First one didn’t last a year. Second didn’t even last 2 months
Color: Gold Size: Size7
I purchased my first ring back in May. It was working great and I loved it! It tracked everything perfectly, and it tracked everything I wanted. The battery worked fine for a while, then I noticed it needed to be charged almost every other day. In October I noticed a crack along the top of the ring, this was confusing because I was never rough with it. It worked for a few weeks after that and then suddenly stopped working, wouldn’t charge. I reached out and customer service was great and even sent me a replacement. The replacement they sent me came mid November. Within the first week I had trouble with charging. Eventually I fixed it by switching the charging port out with a different one. This worked until December 22nd. I reached out again to customer service after the holidays and they told me there was nothing they could do. They ended up offering me a refund which I took, but if I were being honest.. while this ring does have great features.. looks sleek, tracks everything without a subscription, company has decent customer service despite them being hard to reach.. I’d say save your money and buy the oura. I love the concept of what they’re doing, I just feel like there’s a lot of work to be done to actually get it done right. I feel like if they do that they’ll have a lot of sales. I really wish my ring worked because I did like it and felt like the tracking was accurate. ... show more
Reviewed in the United States on January 16, 2026 by Alexis

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