The one output of the Investment element (which has the same name as the element) is the current value of the Investment. This output is a scalar An output consisting of a single value or condition. value with dimensions An output attribute for an element that defines the dimensionality (in terms of Length, Time and other fundamental dimensions) of the output. of currency.
Note that if you wanted to compute the number of units of the Investment at any given time, you would simply divide the Investment output by the Unit Value.