The location of the 18-lead ECG, the order of the limb lead clips is red, yellow, green, and black corresponding to the right wrist, left wrist, left lower ankle, and right lower ankle, respectively. The location of the thoracic leads is V1 lead is located at the 4th intercostal space on the right edge of the sternum; V2 lead is located at the 4th intercostal space on the left edge of the sternum; V4 lead is the 5th intercostal space on the left midclavicular line; V3 lead is located at the midpoint of the line connecting V2 and V4 leads; while V5 lead is located at the left anterior axillary line, at the same level as V4 lead; V6 lead is located at the left midaxillary line, at the same level as V4 lead; V7 lead is located at the left posterior axillary line; lead V8 is located in the left mid-scapular line all at the same level as lead V4; lead V9 is located in the left paraspinal line also at the same level as lead V4; and the positions of V3R, V4R, and V5R in the right chest correspond to the positions of V3, V4, and V5 in the left chest, respectively.