There are many different types of ECG paper and EKG paper, depending on the term you wish to use. The most obvious difference between the paper is the form that the paper is in. Some ECG machines and printers use sheet paper that is typically in an f-fold pattern. This sheet paper can also vary in dimensions of width as well as the number of sheets in a package. The roll style paper is also common in many machines. Like the sheet paper there are various widths, measured in millimeters, as well as various lengths of a roll. In most machines the roll length can be determined by the facility, provided the roll is not too large in circumference to fit into the paper feeder on the machine. Since there are different specifications on each machine exchanging paper is not recommended. However, some paper is approved for several different models and even brands of ECG and EKG machine, which can help to decrease the number of different types of paper you order. This may be an important consideration within a medical clinic or hospital when selecting ECK equipment. What happens if I accidentally order the incorrect paper for my ECG machine? The reputable online medical supply companies do realize that mistakes are made. The specific return policy should be clearly listed on the website and should outline what steps need to be taken to return any incorrectly ordered or incorrectly shipped ECG paper. Most companies require that you get an RAN or return authorization number before shipping the product back. You may be charged return shipping and a restocking fee if the error was in your order. If the company shipped a product in error you should not be charged to return or restock the material. In addition the shipping of the correct product should be done for you at no cost. Most companies have a timeline for returns and some companies will not accept opened product. It is therefore important to check all orders as they arrive and deal with any errors within the timeline indicated on the medical supply company's website.