Package contains: you will get two EKG calipers in classic colors; They are practical for electrocardiogram drafting, nice supplies for school and hospital.Quality material: the EKG calipers measuring tool is made of metal, which is reliable and strong, not easy to rust or deform, and can serve you for a long time.Ruler design: EKG caliper has a scale design on the protective cover, which can be applied as a ruler, and the measurement range is 0 - 2.4 inch; It is perfect for measuring electrocardiogram waveform.Easy to use: end points of electrocardiogram drafting divider are adjustable to the desired length to meet various needs, providing you with a good experience.Portable design: EKG calipers with ruler is about 7.05 x 1.57 inch, lightweight and compact, can fit pockets and pencil cases well, easy to carry and use anytime, anywhere.Colour: blackMaterial: metalPackage Contents:2 sets * EKG Caliper ECG CalipersOnly the above package content, other products are not included.Note: Light 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.