This ECG measurement is the perfect ftool to measure the heart rate, including PR, QRS intervals, cycles, systolic lengths, and ST segments within the paper speed range of 25mm/s and 50mm/s It is a highly versatile toolto analyze ECG reports, on-site cardiac events, and strip chart recordings. It works perfectly on paper and on defibrillator screen. It has a small, lightweight design. The plastic material is durable, transparent, and easily wipes for disinfecting.