Included information on this badge card: Normal sinus rhythm diagram, R wave ruler to measure heart rate, low range and high range measurements for PR interval, QRS complex, and QT interval with accompanying information chart. The EKG ruler badge card is perfect for professionals that read electrocardiograms regularly. The EKG Ruler reference card will fit on any standard sized badge holder or badge reel. This badge card makes a great gift for nurses, EMTs, EKG Techs, and other healthcare professionals. The EKG Ruler badge card is a perfect tool for that hard to remember specific information needed when measuring ECG. Don't get caught unprepared - have this badge card ready at your fingertips!