Crafted from PVC materials, this ruler features clear, wear resistant marking for long terms use and easy portability Great for doctors, nurses, and medicals students who require heart rate analysis tool Enhances your diagnostic capabilities with this essential heart rate measurement tool, a must having for any medicals professional Perfect for use in hospitals, clinics, and educational occasion where heart rate examinations and research is conducted Ensures accurate heart rate measurements with our heart rate ruler, designs to assist medicals professional in analyzing heart health, Manufacturer: HENYGEN