Airgoesin ECG EKG Calipers Ruler Drafting Electrocardiogram Divider<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Blue - EKG ECG Caliper to measure electrocardiogram wave sections. High Quality!</li><li>Adjustable screws for arms loose and tight.</li><li>Brass arms with chrome-plated feels heavier than other materials(stability) .</li><li>Protective plastic cover， 6 cm/2.4 inches molded ruler for easy reference.</li><li>Length: 11.1cm/4.37inches (from top to points).</li></ul></div><img src="http://ecx.images-amazon.com/images/I/41gd%2B1MKpbL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31xApbvjEiL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/41wXC6DW5OL.jpg" noproxy>