Based on this product's specifications, here are some alternatives and similar models
Heart Rate Monitor Polar H10
Summary description:
The Polar H10 heart rate monitor is a reliable device for tracking your heart rate during workouts. It is waterproof up to 30 meters and weighs only 60 grams. Powered by a CR2025 battery, it features a durable housing made of ABS and stainless steel, with a comfortable elastin, polyamide, and polyester band. Perfect for athletes seeking accurate heart rate data.