I have a worksheet that uses a fancy drop down button on a cell to display
changes in an input variable. Does anyone know how to create one?

If someone needs me to elaborate on what I am seeing on the worksheet, here
goes:

1. Worksheet analyses often use input variables in a cell that can be
changed as needed. Thus for example, an interest rate number is often used an
input variable for financial analysis.

2. The usual method is to keep this variable in one place and highlight it;
people can change this number to see how the overall analysis changes. Thus,
I can manually change a 9% interest rate to (say )10% to see what the impact
on a projects profitability will be.

3. But the worksheet I am seeing has a fancy drop down button that, when
clicked, shows a range of intrerest rate options alreayd built in.

How did they do that?