CORE 2 Thermal Sensor — Internal Body Temperature Monitor

The CORE 2 Thermal Sensor is a non-invasive core body temperature monitor designed for athletes who want to track their response to heat in real time during training and competition. It measures core body temperature and skin temperature, helping athletes better manage exertion, cooling, and heat training to improve performance. For sports use, it requires heart rate data from a compatible ANT+ or Bluetooth heart rate monitor, sold separately.

• Type: non-invasive thermal monitoring sensor
• Measurement: core body temperature and skin temperature
• Technology: thermal energy transfer sensor and core body temperature calculation algorithm
• Recommended use: heat training, thermal monitoring during competition, and effort tracking
• Requirement for sports use: compatible heart rate monitor that transmits heart rate via ANT+ or Bluetooth; sold separately
• Training metrics: Heat Strain Index, Heat Zones, Heat Training Load, and Heat Adaptation Score in the CORE ecosystem; availability on external devices varies by model
• Dimensions without clip: 41.9 × 29.4 × 7.1 mm
• Dimensions with clip: 45.1 × 32.6 × 9.6 mm
• Connectivity: Bluetooth Low Energy (BLE) and ANT+, 2.4 GHz band
• Bluetooth connections: up to 3 simultaneous connections
• Battery: rechargeable, non-replaceable; charging via included magnetic USB-C cable
• Battery life: up to 5 days of continuous use
• Sleep mode: up to 30 days between charges, depending on use; activates after 20 min without wearing the sensor
• Charging time: typically 3–4 h, from a computer USB port or wall charger
• Water resistance: IPX7, up to 1.5 m
• Measurement while submerged: readings underwater cannot be used
• Sauna and steam: not suitable for wearing in a sauna or steam room
• Body temperature range: 36–42 °C
• Operating ambient temperature: −20–45 °C; in cold environments, keep the sensor in contact with the body
• Operating device temperature: 10–45 °C
• Storage: 0–25 °C, in a dry place
• Validation: mean difference of −0.01 to +0.23 °C compared with reference core temperature, according to CORE
• Mounting: attaches to the torso, preferably under the armpit, using the clip on the heart rate monitor strap, with the back in contact with the skin and the logo facing outward
• App: CORE for iOS and Android; thermal data, heart rate monitor pairing, and firmware updates
• Garmin: compatible models via the CORE Connect IQ data field or native pairing on recent models; functions vary by device
• Wahoo: ELEMNT ACE, BOLT 3, and ROAM 3 with full integration; BOLT 2 and ROAM 2 without Heat Strain Index or Heat Zones; RIVAL not compatible
• COROS: compatible devices, including DURA, via Bluetooth and updated firmware; metrics vary by generation
• Suunto: Suunto 9 with compatible firmware and the CORE SuuntoPlus app; live display, without saving CORE data to the FIT file
• Hammerhead: Karoo with updated firmware; live core and skin temperature in the FIT file; TrainingPeaks does not display these metrics from Karoo activities
• Charging indicator: red LED; turns off when charging is complete
• Status indicator: green LED for battery level, connection, and heart rate monitor detection
• Modular design: detachable clip for easy charging and placement
• Purpose: sports tracking; according to CORE, it does not have FDA or CE approval as a medical device

• Sensor: CORE 2 Thermal Sensor
• Clip: CORE 2 heart rate monitor strap clip
• Charging: magnetic USB-C cable
• Documentation: product information guide
• Packaging: fully recyclable
• Sold separately: heart rate monitor and chest strap

Clipless sensor: 8,6 g

Sensor with clip: 11,4 g

Legal warranty in Spain: 3 years from delivery for lack of conformity in new goods sold to consumers.

CORE commercial warranty: 2 years in the European Union for material or manufacturing defects under normal use. CORE may repair, replace, or refund the sensor in accordance with its policy. Exclusions apply for wear and tear, misuse, accidents, cosmetic damage that does not affect functionality, and modifications, among others. This warranty does not limit the legal warranty.