Features: You will get 2pcs ECG calipers with a scale independent coat in different color,,and 2 clear ECG ruler, which can apply to measure ECG waveforms; The ECG calipers pen have a plastic clip that can be easily fixed to the Nursings uniform. Crafted from quality metal and ABS, this calipers set is reliable and easy to clean and store. Adjust Length:Ends point can be adjusted to the length you need, accurate and stable. Adjust tightness: adjusting screw is used to loosen and tighten the arms. For Measuring: This ECG calipers set can largely simplifies mark, measuring, drafting, dividing and so on on electrocardiograph. Specifications: Material:ABS,Metal Color:2Pcs Black,Blue & Pink,Pink & Black,Black & Blue Size:Approx.97mm/3.82''x17mm/0.67'',38mm/1.5''x90mm/3.54'' Package Includes: 1Set ECG ECG Calipers note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color.