Comparison

CORE Thermal Sensor vs Hammerhead Companion

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

CORE Thermal Sensor

This app continuously monitors your core body temperature and thermal strain, providing critical data for heat training and optimal race performance. It helps athletes of all levels improve their training and achieve better results.

Highlights
  • Continuous core body temperature monitoring
  • Real-time Heat Strain Index
  • Heat Zones for training and racing
  • Heat Training Load and Adaptation Score
  • Passive heat training tracking
  • Data trends and historical analysis
  • Connectivity with sports devices
Features
Read full description

The CORE Thermal Sensor accurately measures your core body temperature and thermal strain on your body – continuously and non-invasively. Thermal data and insights are critical for facilitating safe and effective heat training and for performing optimally on race day. Designed for athletes at all levels, CORE will help to improve your training and performance in your personal adventures or races. IMPORTANT: The CORE app is designed to work with the CORE device which you can order at www.corebodytemp.com Here's how it works: • Set up your CORE sensor: connect your heart rate monitor and sports devices for optimal sensor use. • Measure your thermal vitals during training: mount the newly designed clip on your heart rate strap and snap in the CORE sensor. Shake the sensor to wake it up, wear it and track your thermal data. • Core body temperature: the interior temperature deep in your body, including organs and other tissues. A critical measure during sports, it can reach up to 40°C (104°F) during vigorous activity in hot environments. Be aware that hotter is not better – cooler is faster. • Heat Strain Index: A combination of your core body temperature and skin temperature representing the thermal strain on your body. The real-time feedback on how hard your body is working to stay cool, delivering a value from 0 (no heat strain) to around 10 (extremely high heat strain). • Heat Zones: Your Heat Strain Index divided into easy-to-use zones. Heat Zone 3 will likely lead to a performance loss, BUT it is the needed stimuli to create adaptations in your body. During heat training, strive for time in heat zone 3. During racing, stay cool and prevent a performance loss by staying in heat zone 1 or 2. • Heat Training Load: a cumulative daily metric of the heat strain on your body. A daily value of 10 out of 10 indicates ideal contribution to heat adaptations. More is not always better! • Heat Adaptation Score: Track your heat adaptations over time with effective heat training. Get a heat champion to perform best in the heat. Long-term heat training will most likely lead to improvements also in cool conditions. • Add your passive heat training: Supplementing your active heat training or general training with passive heat exposure in a sauna or hot bath. You can track your sessions in the app manually, contributing to your heat adaptation score. NOTE: do NOT take your CORE sensor into the sauna or hot environments. What else you can do in the CORE app: • Dig into the details: See a breakdown of your thermal data, and even see trends across days, weeks and months. • Share your CORE metrics with your friends through the social sharing feature, earning more kudos and likes • Connect your connectivity accounts (e.g. Garmin) to directly synchronize your data after the training. • Update your sensor to the latest firmware ensuring having the best sensor functionality. Note: CORE provides products and services designed for general fitness and training purposes. For accurate measurement readings during sports, a connection to a heart rate monitor is necessary. CORE products and services are not medical devices, not intended to treat or diagnose any disease, and should not be used as a substitute for professional medical advice, diagnosis or treatment. All content available through CORE products and services is for general informational purposes only.

About

Hammerhead Companion

Seamlessly transfer ride data, routes, and workouts to your Karoo bike computer. Sync with popular training platforms and use your phone's maps for navigation. Stay connected with live tracking and phone notifications on your device.

Highlights
  • Ride upload to training platforms
  • Send locations from phone maps to Karoo
  • Sync routes without Wi-Fi
  • Workout synchronization
  • Live tracking sharing
  • Phone notifications on Karoo
Features
Read full description

Enhance your cycling experience with the Hammerhead Companion App! Transfer crucial data from your mobile device to your Karoo with - or without - Wi-Fi. - Ride Upload: Automatically upload your ride to your favorite training platforms like Strava, Ride With GPS, TrainingPeaks, and more! - Route To Point: Pull up Google or Apple Maps on your phone and send a pinned location directly to your Karoo via the Companion App. - Route Sync: Instantly sync routes from the Hammerhead Dashboard to Karoo without Wi-Fi. The Hammerhead Companion App allows you to easily share routes with friends or load a route on the fly. - Workout Sync: Connect to your 3rd party training platforms wherever you are so you never miss a workout. Adjust your workout for the day and Karoo will sync it automatically. - Live Tracking: Quickly share your live tracking link utilizing your phone’s native share menu and give your friends and family peace of mind while you’re out on the road. - Phone Notifications: See your phone’s notifications on your Hammerhead Karoo when you ride. The Hammerhead Companion App is designed specifically for use with the all-new Hammerhead Karoo bike computer. Visit hammerhead.io to learn more.

Screenshots

CORE Thermal Sensor4 screens
Hammerhead Companion4 screens

Verdict

The call

The clearest difference is rating: CORE Thermal Sensor at 2.5 against Hammerhead Companion's 2.0. CORE Thermal Sensor also leads on review sentiment (19% vs 10%) and iOS requirement (15.1 vs 17.6). Hammerhead Companion's advantage is update cadence (monthly vs every 2 months). On price, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

CORE Thermal Sensor holds the better App Store score, 2.5 against 2.0. Both are backed by a comparable volume of ratings — 35 and 95 respectively. Written reviews point the same way: 19% of CORE Thermal Sensor's written reviews are positive against 10% of Hammerhead Companion's.

UpkeepUpdate frequency

CORE Thermal Sensor ships an update every 2 months, Hammerhead Companion monthly. The most recent releases landed on November 3, 2026 and November 4, 2026 respectively.

Scorecard4 real differences · 6 level
CORE Thermal Sensor versus Hammerhead Companion: the parameters behind the verdict, then further details
ParameterCORE Thermal SensorHammerhead Companion
PriceFreeFree
Rating2.5 (35 ratings) — better2.0 (95 ratings)
Positive reviews18.8% of reviews — better9.7% of reviews
Number of ratings3595 — better
Update frequencyEvery 2 monthsMonthly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.1 — better17.6
Further details — not scored
Size55 MB28 MB
Age rating4+4+
Developergreenteg AGSRAM LLC

Customer experience

CORE Thermal Sensor

All ratings35 ratings
Positive22.9%
Neutral20.0%
Negative57.1%
Written reviews48 reviews
Positive18.8%
Neutral25.0%
Negative56.3%

Hammerhead Companion

All ratings95 ratings
Positive22.1%
Neutral5.3%
Negative72.6%
Written reviews155 reviews
Positive9.7%
Neutral1.9%
Negative88.4%

In-app purchases

None

CORE Thermal Sensor

No in-app purchases

None

Hammerhead Companion

No in-app purchases

Questions

Is CORE Thermal Sensor free?
CORE Thermal Sensor is free to download, with no in-app purchases.
Is Hammerhead Companion free?
Hammerhead Companion is free to download, with no in-app purchases.
Which has better reviews, CORE Thermal Sensor or Hammerhead Companion?
CORE Thermal Sensor is rated higher. CORE Thermal Sensor averages 2.5 out of 5 from 35 ratings, while Hammerhead Companion averages 2.0 from 95 ratings.
Do CORE Thermal Sensor or Hammerhead Companion have ads?
Neither CORE Thermal Sensor nor Hammerhead Companion shows ads.
Which is updated more often, CORE Thermal Sensor or Hammerhead Companion?
CORE Thermal Sensor ships an update every 2 months, and Hammerhead Companion monthly. Most recently, CORE Thermal Sensor was updated on November 3, 2026 and Hammerhead Companion on November 4, 2026.

Other comparisons