EKG caliper measuring tool set: you will get 2 EKG calipers with a scale coat, and 2 transparent ECG rulers, which can be applied to measure ECG waveform; The EKG caliper pen has a clip that can be easily fixed to the nursing uniform Adjustable and Convenient: which is convenient to carry in the pocket; The needle tip is fixed with screws, and the length of the 2 needles can be adjusted; The 2 corners are fixed with screws outside, which is convenient to adjust the tightness of the 2 corners; and Portable: which can be suitable for rapid basic ECG measurement on the paper and screen of patient monitor defibrillator; Also suitable for routine use and emergency ; It has the advantages of light weight and small volume Reliable and reusable: the transparent ECG ruler is made of large-scale transparent plastic, which is reliable and has a protective sleeve for longer service life; The 2 legs of the ECG calipers for nurses , which is reliable to use, wear-resistant and not easy to blister Thoughtful gift: the ECG calipers measuring tool for nursing is a thoughtful your friends who are nurses or nursing students, which is a practical them Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Material: Metal+Plastic colour: black+pink Package Contents: 2 x ECG Sub-Gauges 2 x heart rate rulers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.