A medical device including an inflation element, such as a syringe, and a balloon catheter in which the inflation element includes a series of indicia to which an operative portion of the inflation device can be aligned. The indicia directly correspond to a particular balloon diameter. A method of inflating a balloon to at least two desired diameters in a body lumen and determining the inflation diameter of the balloon within the body lumen. A method of calibrating the inflation device to allow a user to inflate a balloon to a desired diameter.