Based on this product's specifications, here are some alternatives and similar models
Core CORE 2 Body Temperature Sensor
Summary description:
The Core CORE 2 is a wearable sensor designed for continuous, real-time monitoring of core body temperature. Ideal for athletes and professionals, it provides accurate physiological data to help optimize performance and safety during physical activity. The device integrates seamlessly with sports watches and cycling computers, offering reliable tracking for endurance training and health monitoring.