Nickel-titanium alloys have excellent corrosion resistance and good mechanical strength. However, the most interesting property is that they are a type of shape memory alloy (SMA). They can be formed into a specific shape above a certain high temperature, called the transition temperature. When cool, the part can be deformed to a certain degree, but if it is heated back up to its transition temperature, it will resume its original shape. The exact temperature at which this change takes place can be adjusted by changing the composition of the alloy. These alloys are especially useful in medical applications. For example, stents can be inserted in their compressed form but will expand to their final shape once in the body. Nickel-titanium alloys are also known by the name Nitinol®.