Typical normal coronary artery pressures are in the <200 mmHg range (27 kPa). The hydraulic pressures applied within the balloon may extend to as high as 19000 mmHg (2,500 kPa). Prevention of over-enlargement is achieved by choosing balloons manufactured out of high tensile strength clear plastic membranes. The balloon is initially folded around the catheter, near the tip, to create a small cross-sectional profile to facilitate passage through luminal stenotic areas, and is designed to inflate to a specific pre-designed diameter. If over-inflated, the balloon material simply tears and allows the inflating radiocontrast agent to simply escape into the blood.