---
product_id: 685582422
title: "femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8)"
brand: "femometer"
price: "¥50857"
currency: JPY
in_stock: true
reviews_count: 13
category: "Femometer"
url: https://www.desertcart.jp/products/685582422-femometer-ring-gen2-size-before-you-buy-smart-ring-women
store_origin: JP
region: Japan
---

# Pro sleep stage & blood oxygen insights 1,400+ nightly BBT measurements 24/7 heart rate & HRV tracking femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8)

**Brand:** femometer
**Price:** ¥50857
**Availability:** ✅ In Stock

## Summary

> 💍 Own your health journey with the smartest ring on your finger.

## Quick Answers

- **What is this?** femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) by femometer
- **How much does it cost?** ¥50857 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/685582422-femometer-ring-gen2-size-before-you-buy-smart-ring-women)

## Best For

- femometer enthusiasts

## Why This Product

- Trusted femometer brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Power That Lasts:** Up to 35 days battery life with quick-charge case, lifetime app subscription, and seamless iOS/Android compatibility.
- • **Sleep Like a Pro:** Deep, Light, REM sleep stages plus blood oxygen monitoring deliver personalized sleep scores & tips.
- • **All-Day Health Vigilance:** Continuous heart rate, HRV, steps & calorie tracking synced to your lifetime-free femometer app.
- • **Elegance Meets Endurance:** Ultra-slim 2.7mm ceramic ring, water-resistant to 100m, featherlight 3.3g for 24/7 stylish wear.
- • **Cycle Tracking Revolution:** Advanced BBT tech with 1,400+ nightly temps ensures pinpoint ovulation & cycle predictions trusted by 15M+ women.

## Overview

The femometer Ring Gen2 is a sleek, ceramic smart ring designed for women to monitor heart rate, HRV, sleep stages, blood oxygen, and fertility cycles with revolutionary BBT technology. It offers continuous 24/7 health tracking, professional sleep insights, and up to 35 days of battery life, all synced to a lifetime-free app trusted by over 15 million women worldwide. Durable, water-resistant, and ultra-lightweight, it’s the ultimate health companion for the modern professional woman.

## Description

desertcart.com: femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) | Sleep, Heart Rate & Cycle Monitoring, No Subscription, Women's Health & Fertility Tracker with BBT Technology : Electronics

Review: Love it so far! - So far liking the product and had great costumer service when I got my ring, the battery level died within a day I sent over the details to the company and they resent me a new ring. The battery lasting long was one of my top likes. It’s been doing the trick for what I needed especially love the sleeping tracking feature. And AI insights based on measurements from the ring. I do wish I would have gotten a ring sizer and knew my ring size before or went up a size.
Review: Great cycle tracking! - 📈 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. 🤰🍑🍋 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. 👣💤 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 👍

## Features

- 24/7 HEALTH COMPANION: Continuous heart rate monitoring and HRV tracking provide stress insights and health trends. Track daily activity, steps, and calorie burn. All health data syncs seamlessly with the lifetime free femometer app.
- PROFESSIONAL SLEEP INSIGHTS: Track sleep stages (Deep, Light, REM), blood oxygen levels while you rest. Get detailed sleep scores and personalized recommendations.
- ADVANCED CYCLE TRACKING: Revolutionary BBT technology with 1,400+ nightly temperature measurements provides accurate cycle predictions and ovulation detection. Part of trusted femometer ecosystem with 15M+ women worldwide.
- COMFORT MEETS ELEGANCE: Just 2.7mm. Premium ceramic exterior with aluminum core ensures durability while weighing only 3.3g. Scratch-resistant, water-resistant to 100m, and designed for 24/7 wear. Size First with femometer Sizing Kit.
- SIMPLE & RELIABLE: Up to 35-day battery life with quick charging case (stores 5 full charges). Pair with femometer app to get lifetime subscription. Compatible with iOS and Android. Includes 1-year warranty and dedicated customer support. Regular firmware updates ensure continuous improvement.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0DJ31JPRB |
| Additional Features | Activity Tracker, Cycle Tracking, Lightweight, Wireless Charging |
| Age Range Description | Adult |
| Band Material Type | Ceramic, Aluminum |
| Battery Average Life | 7 days |
| Battery Capacity | 21 milliamp_hours |
| Battery Cell Composition | Lithium Ion |
| Battery Cell Type | Lithium Ion |
| Best Sellers Rank | #7,648 in Electronics ( See Top 100 in Electronics ) #34 in Smart Rings |
| Brand | femometer |
| Built-In Media | User Manual |
| Color | Gold |
| Communication Feature | Bluetooth |
| Compatible Devices | Smartphone |
| Compatible Phone Models | All current iPhone models, all current Android models |
| Connectivity Technology | Bluetooth |
| Customer Reviews | 3.9 out of 5 stars 298 Reviews |
| Display Type | No Display |
| GPS Geotagging Functionality | No GPS |
| Human Interface Input | Buttons |
| Item Dimensions D x W x H | 0.11"D x 0.11"W x 0.11"H |
| Item Weight | 3.7 g |
| Manufacturer | LOLLIPOP TECHNOLOGY (HANGZHOU) CO., LTD |
| Metrics Measured | Heart Rate Monitor, Sleep Duration, Body Temperature, Activity Tracker |
| Model Number | 42616f15-b2f2-4c4a-9129-287f3771f45c |
| Operating System | Wear OS 3.0 |
| Screen Size | 1 inches |
| Shape | Round |
| Special Feature | Activity Tracker, Cycle Tracking, Lightweight, Wireless Charging |
| Style Name | Ring Only |
| Supported Application | Alarm, Fitness Tracker, Heart Rate Monitor, Sleep Monitor, Time Display |
| Target Audience | Girls, Women |
| UPC | 810115236429 |
| Unit Count | 1 Count |
| Warranty Description | 1 Year Manufacturer |
| Warranty Type | Standard |
| Water Resistance Depth | 1.5 meters |
| Water Resistance Level | Water Resistant |
| Wearable Computer Type | Smart Ring |
| Wireless Communication Standard | Bluetooth |
| Wireless Compability | Bluetooth |

## Product Details

- **Battery Capacity:** 21 milliamp_hours
- **Battery Cell Composition:** Lithium Ion
- **Brand:** femometer
- **Connectivity Technology:** Bluetooth
- **GPS:** No GPS
- **Operating System:** Wear OS 3.0
- **Screen Size:** 1 inches
- **Shape:** Round
- **Special Feature:** Activity Tracker, Cycle Tracking, Lightweight, Wireless Charging
- **Wireless Communication Standard:** Bluetooth

## Images

![femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) - Image 1](https://m.media-amazon.com/images/I/51BYpkcMRZL.jpg)
![femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) - Image 2](https://m.media-amazon.com/images/I/71fH0WXqzLL.jpg)
![femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) - Image 3](https://m.media-amazon.com/images/I/61lBZtOYE8L.jpg)
![femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) - Image 4](https://m.media-amazon.com/images/I/61i-iutcvKL.jpg)
![femometer Ring Gen2 - Size Before You Buy, Smart Ring for Women(Size 8) - Image 5](https://m.media-amazon.com/images/I/71x1X9PLiaL.jpg)

## Available Options

This product comes in different **Color, Size** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Love it so far!
*by A***A on September 25, 2026*

So far liking the product and had great costumer service when I got my ring, the battery level died within a day I sent over the details to the company and they resent me a new ring. The battery lasting long was one of my top likes. It’s been doing the trick for what I needed especially love the sleeping tracking feature. And AI insights based on measurements from the ring. I do wish I would have gotten a ring sizer and knew my ring size before or went up a size.

### ⭐⭐⭐⭐⭐ Great cycle tracking!
*by A***T on August 22, 2026*

📈 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. 🤰🍑🍋 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. 👣💤 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 👍

### ⭐⭐⭐⭐ Fermometer Gen2 Ring Review
*by C***A on June 30, 2026*

I have loved my ring! I have only been using it for a couple of weeks but it was a great investment. The best part is that there is no subscription fee needed to use the ring. It's a one time purchase and you can use it for life! It tracks everything you could ask for and is just like the Oura ring but more affordable and better. The only issue I ran into is when I ordered the ring I had to go through Amazon and not the website directly. It sucked becuse I was using a discount code from social media and Amazon would not honor the code so I had to pay a little more than I was going to if I could order through the website directly. The website only has certain size options for certain rings so make sure to check all the size option before ordering the ring. They send you a sizing kit once ordered so just make sure it will have all the sizes you think you might be or want to try. I ordered a size 11 and it fits perfect. I went up a size just to be safe and it was a good idea cause even if my finger swells it still fits and can take it off at any point doesn't get stuck. Otherwise it's been the best investment I have made for my health and is exactly what I was looking for when wanting a ring!

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**Shop now:** [https://www.desertcart.jp/products/685582422-femometer-ring-gen2-size-before-you-buy-smart-ring-women](https://www.desertcart.jp/products/685582422-femometer-ring-gen2-size-before-you-buy-smart-ring-women)

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-10-02*