Based on this product's specifications, here are some alternatives and similar models
Heart Rate Monitor Breast Polar H10
Summary description:
The Polar H10 heart rate monitor offers accurate heart rate measurement with ANT+ data transfer. It features a comfortable elastin, polyamide, and polyester band, weighs only 60 g, and is powered by a CR2025 battery. Available in black and blue, it is designed for optimal performance during workouts.